Methods and apparatus for mimo transmission

ABSTRACT

Methods for multiple input-multiple output (MIMO) transmission are provided herein. A method may include sensing, using at least one of a plurality of antenna chains, radio frequency (RF) energy on a channel in a first time duration and may indicate the channel is busy. RF energy may be sensed on the channel using the at least one of the plurality of antenna chains in a second time duration and may indicate the channel is not busy. A method may include sending energy level sensed during the second time duration, a frame using the at least one of the plurality of antenna chains. The frame may indicate timing information associated with a MIMO transmission. The MIMO transmission may be sent using the indicated timing information and the at least one of the plurality of antenna chains.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/621,133 filed Dec. 10, 2019, which is the U.S. National Stage, under35 U.S.C. § 371, of International Application No. PCT/US2018/037510filed Jun. 14, 2018, which claims the benefit of U.S. ProvisionalApplication Ser. No. 62/519,808 filed Jun. 14, 2017, U.S. ProvisionalApplication Ser. No. 62/557,573 filed Sep. 12, 2017, and U.S.Provisional Application Ser. No. 62/567,348 filed Oct. 3, 2017, thecontents of which are hereby incorporated by reference herein.

BACKGROUND

The IEEE Standard for information technology relates totelecommunications and information exchange between systems local andarea networks. Wireless LAN (WLAN) Medium Access Control (MAC) andPhysical Layer (PHY) specifications may require improvements as new usesand technical abilities are achieved.

Beam refinement is a process where a station (STA) can improve itsantenna configuration (or antenna weight vectors) for both transmissionand reception.

Precoding at millimeter wave frequencies may be digital, analog or ahybrid of digital and analog. Digital precoding may be precise and canbe combined with equalization. Analog beamforming may overcome having alimited number of RF chains by using analog phase shifters on eachantenna element. In hybrid beamforming, a precoder may be dividedbetween analog and digital domains.

SUMMARY

Methods for multiple input-multiple output (MIMO) transmission areprovided herein. A method may include sensing, using at least one of aplurality of antenna chains, radio frequency (RF) energy on a channel ina first time duration and may indicate the channel is busy. RF energymay be sensed on the channel using the at least one of the plurality ofantenna chains in a second time duration and may indicate the channel isnot busy. A method may include sending energy level sensed during thesecond time duration, a frame using the at least one of the plurality ofantenna chains. The frame may indicate timing information associatedwith a MIMO transmission. The MIMO transmission may be sent using theindicated timing information and the at least one of the plurality ofantenna chains.

BRIEF DESCRIPTION OF THE DRAWINGS

A more detailed understanding may be had from the following description,given by way of example in conjunction with the accompanying drawings,wherein like reference numerals in the figures indicate like elements,and wherein:

FIG. 1A is a system diagram illustrating an example communicationssystem in which one or more disclosed embodiments may be implemented;

FIG. 1B is a system diagram illustrating an example wirelesstransmit/receive unit (WTRU) that may be used within the communicationssystem illustrated in FIG. 1A according to an embodiment;

FIG. 10 is a system diagram illustrating an example radio access network(RAN) and an example core network (CN) that may be used within thecommunications system illustrated in FIG. 1A according to an embodiment;

FIG. 1D is a system diagram illustrating a further example RAN and afurther example CN that may be used within the communications systemillustrated in FIG. 1A according to an embodiment;

FIG. 2 is a diagram of an example of PPDU formats;

FIG. 3 is diagram of an example of transmission block diagram ControlPHY;

FIG. 4 is a diagram of an example of sector level sweep;

FIG. 5 is a diagram of an example of SSW frame format;

FIG. 6 is a diagram of an example of SSW field format;

FIG. 7A is a diagram of an example of SSW feedback field format whentransmitted as part of an ISS;

FIG. 7B is a diagram of an example of SSW feedback field format when nottransmitted as part of an ISS;

FIG. 8 is a diagram of an example of a BRP TRN-RX packet;

FIG. 9 is a diagram of an example 802.11ay PPDU format;

FIG. 10 is a diagram of an example where all PAs excited by all theweights;

FIG. 11 is a diagram of an example where different PAs excited byseparate weights;

FIG. 12 is a diagram of an example procedure hybrid precoding forOFDM-based mmWave MIMO;

FIG. 13 is a diagram of an example existing DMG beam refinement element;

FIG. 14 is a diagram of an example of a modified DMG beam refinementelement;

FIG. 15 is a diagram of an example TRN structure for digital precodingsounding;

FIG. 16 is a diagram of an example TRN structure for digital precodingsounding;

FIG. 17 is a diagram of an example TRN structure for hybrid beamformingsounding;

FIG. 18 is a diagram of an example TRN structure;

FIG. 19 is a diagram of an example of temporal characteristics in timedomain for different cases;

FIG. 20 is a diagram of an example of temporal characteristics in timedomain for different cases;

FIG. 21 is a diagram of an example of flexible TRN generation with OFDMand beams;

FIG. 22 is a diagram of an example of TRN structure for hardwarenon-linearities;

FIG. 23 is a diagram of an example of transmission and reception of CEFwith phase rotations;

FIG. 24 is a diagram of an example process of determining the startingpoint of a TRN field;

FIG. 25A is a diagram of an example of forward initiator only HBFprotocol frame exchange for SU-MIMO;

FIG. 25B is a diagram of an example forward responder only HBF protocolframe exchange for SU-MIMO;

FIG. 25C is a diagram of an example forward initiator and responder HBFprotocol frame exchange for SU-MIMO;

FIG. 26A is a diagram of an example reverse initiator only HBF protocolframe exchange for SU-MIMO;

FIG. 26B is a diagram of an example reverse responder only HBF protocolframe exchange for SU-MIMO;

FIG. 26C is a diagram of an example reverse initiator and responder HBFprotocol frame exchange for SU-MIMO;

FIG. 26D is a diagram of another example reverse initiator and responderHBF protocol frame exchange for SU-MIMO;

FIG. 27 is a diagram of an example of forward HBF protocol frameexchange for MU-MIMO;

FIG. 28 is a diagram of an example of reverse (uplink) HBF protocol forMU-MIMO;

FIG. 29 is a diagram of an example of beamforming capability fieldsformat;

FIG. 30 is a diagram of an example HBF control field;

FIG. 31 is a diagram of an example HBF frame format;

FIG. 32 is a diagram of an example HBF frame format;

FIG. 33A is a diagram of an example HBF MU-Grant frame format;

FIG. 33B is a diagram of an example HBF MU-Grant frame format;

FIG. 34 is a diagram of an example EDMG Channel Feedback for PPDU Mode;

FIG. 35 is a diagram of an example EDMG Precoder Feedback for PPDU Mode;

FIG. 36 is a diagram of an example EDMG HBF Feedback for OFDM PPDU Mode;and

FIG. 37 is a diagram of an example HBF Feedback in a frame for SC andOFDM PPDU Modes.

DETAILED DESCRIPTION

FIG. 1A is a diagram illustrating an example communications system 100in which one or more disclosed embodiments may be implemented. Thecommunications system 100 may be a multiple access system that providescontent, such as voice, data, video, messaging, broadcast, etc., tomultiple wireless users. The communications system 100 may enablemultiple wireless users to access such content through the sharing ofsystem resources, including wireless bandwidth. For example, thecommunications systems 100 may employ one or more channel accessmethods, such as code division multiple access (CDMA), time divisionmultiple access (TDMA), frequency division multiple access (FDMA),orthogonal FDMA (OFDMA), single-carrier FDMA (SC-FDMA), zero-tailunique-word DFT-Spread OFDM (ZT UW DTS-s OFDM), unique word OFDM(UW-OFDM), resource block-filtered OFDM, filter bank multicarrier(FBMC), and the like.

As shown in FIG. 1A, the communications system 100 may include wirelesstransmit/receive units (WTRUs) 102 a, 102 b, 102 c, 102 d, a RAN104/113, a CN 106/115, a public switched telephone network (PSTN) 108,the Internet 110, and other networks 112, though it will be appreciatedthat the disclosed embodiments contemplate any number of WTRUs, basestations, networks, and/or network elements. Each of the WTRUs 102 a,102 b, 102 c, 102 d may be any type of device configured to operateand/or communicate in a wireless environment. By way of example, theWTRUs 102 a, 102 b, 102 c, 102 d, any of which may be referred to as a“station” and/or a “STA”, may be configured to transmit and/or receivewireless signals and may include a user equipment (UE), a mobilestation, a fixed or mobile subscriber unit, a subscription-based unit, apager, a cellular telephone, a personal digital assistant (PDA), asmartphone, a laptop, a netbook, a personal computer, a wireless sensor,a hotspot or Mi-Fi device, an Internet of Things (IoT) device, a watchor other wearable, a head-mounted display (HMD), a vehicle, a drone, amedical device and applications (e.g., remote surgery), an industrialdevice and applications (e.g., a robot and/or other wireless devicesoperating in an industrial and/or an automated processing chaincontexts), a consumer electronics device, a device operating oncommercial and/or industrial wireless networks, and the like. Any of theWTRUs 102 a, 102 b, 102 c and 102 d may be interchangeably referred toas a UE.

The communications systems 100 may also include a base station 114 aand/or a base station 114 b. Each of the base stations 114 a, 114 b maybe any type of device configured to wirelessly interface with at leastone of the WTRUs 102 a, 102 b, 102 c, 102 d to facilitate access to oneor more communication networks, such as the CN 106/115, the Internet110, and/or the other networks 112. By way of example, the base stations114 a, 114 b may be a base transceiver station (BTS), a Node-B, an eNodeB, a Home Node B, a Home eNode B, a gNB, a NR NodeB, a site controller,an access point (AP), a wireless router, and the like. While the basestations 114 a, 114 b are each depicted as a single element, it will beappreciated that the base stations 114 a, 114 b may include any numberof interconnected base stations and/or network elements.

The base station 114 a may be part of the RAN 104/113, which may alsoinclude other base stations and/or network elements (not shown), such asa base station controller (BSC), a radio network controller (RNC), relaynodes, etc. The base station 114 a and/or the base station 114 b may beconfigured to transmit and/or receive wireless signals on one or morecarrier frequencies, which may be referred to as a cell (not shown).These frequencies may be in licensed spectrum, unlicensed spectrum, or acombination of licensed and unlicensed spectrum. A cell may providecoverage for a wireless service to a specific geographical area that maybe relatively fixed or that may change over time. The cell may furtherbe divided into cell sectors. For example, the cell associated with thebase station 114 a may be divided into three sectors. Thus, in oneembodiment, the base station 114 a may include three transceivers, i.e.,one for each sector of the cell. In an embodiment, the base station 114a may employ multiple-input multiple output (MIMO) technology and mayutilize multiple transceivers for each sector of the cell. For example,beamforming may be used to transmit and/or receive signals in desiredspatial directions.

The base stations 114 a, 114 b may communicate with one or more of theWTRUs 102 a, 102 b, 102 c, 102 d over an air interface 116, which may beany suitable wireless communication link (e.g., radio frequency (RF),microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet(UV), visible light, etc.). The air interface 116 may be establishedusing any suitable radio access technology (RAT).

More specifically, as noted above, the communications system 100 may bea multiple access system and may employ one or more channel accessschemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and the like. Forexample, the base station 114 a in the RAN 104/113 and the WTRUs 102 a,102 b, 102 c may implement a radio technology such as Universal MobileTelecommunications System (UMTS) Terrestrial Radio Access (UTRA), whichmay establish the air interface 115/116/117 using wideband CDMA (WCDMA).WCDMA may include communication protocols such as High-Speed PacketAccess (HSPA) and/or Evolved HSPA (HSPA+). HSPA may include High-SpeedDownlink (DL) Packet Access (HSDPA) and/or High-Speed UL Packet Access(HSUPA).

In an embodiment, the base station 114 a and the WTRUs 102 a, 102 b, 102c may implement a radio technology such as Evolved UMTS TerrestrialRadio Access (E-UTRA), which may establish the air interface 116 usingLong Term Evolution (LTE) and/or LTE-Advanced (LTE-A) and/orLTE-Advanced Pro (LTE-A Pro).

In an embodiment, the base station 114 a and the WTRUs 102 a, 102 b, 102c may implement a radio technology such as NR Radio Access, which mayestablish the air interface 116 using New Radio (NR).

In an embodiment, the base station 114 a and the WTRUs 102 a, 102 b, 102c may implement multiple radio access technologies. For example, thebase station 114 a and the WTRUs 102 a, 102 b, 102 c may implement LTEradio access and NR radio access together, for instance using dualconnectivity (DC) principles. Thus, the air interface utilized by WTRUs102 a, 102 b, 102 c may be characterized by multiple types of radioaccess technologies and/or transmissions sent to/from multiple types ofbase stations (e.g., a eNB and a gNB).

In other embodiments, the base station 114 a and the WTRUs 102 a, 102 b,102 c may implement radio technologies such as IEEE 802.11 (i.e.,Wireless Fidelity (WiFi), IEEE 802.16 (i.e., Worldwide Interoperabilityfor Microwave Access (WiMAX)), CDMA2000, CDMA2000 1×, CDMA2000 EV-DO,Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), InterimStandard 856 (IS-856), Global System for Mobile communications (GSM),Enhanced Data rates for GSM Evolution (EDGE), GSM EDGE (GERAN), and thelike.

The base station 114 b in FIG. 1A may be a wireless router, Home Node B,Home eNode B, or access point, for example, and may utilize any suitableRAT for facilitating wireless connectivity in a localized area, such asa place of business, a home, a vehicle, a campus, an industrialfacility, an air corridor (e.g., for use by drones), a roadway, and thelike. In one embodiment, the base station 114 b and the WTRUs 102 c, 102d may implement a radio technology such as IEEE 802.11 to establish awireless local area network (WLAN). In an embodiment, the base station114 b and the WTRUs 102 c, 102 d may implement a radio technology suchas IEEE 802.15 to establish a wireless personal area network (WPAN). Inyet another embodiment, the base station 114 b and the WTRUs 102 c, 102d may utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE,LTE-A, LTE-A Pro, NR etc.) to establish a picocell or femtocell. Asshown in FIG. 1A, the base station 114 b may have a direct connection tothe Internet 110. Thus, the base station 114 b may not be required toaccess the Internet 110 via the CN 106/115.

The RAN 104/113 may be in communication with the CN 106/115, which maybe any type of network configured to provide voice, data, applications,and/or voice over internet protocol (VoIP) services to one or more ofthe WTRUs 102 a, 102 b, 102 c, 102 d. The data may have varying qualityof service (QoS) requirements, such as differing throughputrequirements, latency requirements, error tolerance requirements,reliability requirements, data throughput requirements, mobilityrequirements, and the like. The CN 106/115 may provide call control,billing services, mobile location-based services, pre-paid calling,Internet connectivity, video distribution, etc., and/or performhigh-level security functions, such as user authentication. Although notshown in FIG. 1A, it will be appreciated that the RAN 104/113 and/or theCN 106/115 may be in direct or indirect communication with other RANsthat employ the same RAT as the RAN 104/113 or a different RAT. Forexample, in addition to being connected to the RAN 104/113, which may beutilizing a NR radio technology, the CN 106/115 may also be incommunication with another RAN (not shown) employing a GSM, UMTS, CDMA2000, WiMAX, E-UTRA, or WiFi radio technology.

The CN 106/115 may also serve as a gateway for the WTRUs 102 a, 102 b,102 c, 102 d to access the PSTN 108, the Internet 110, and/or the othernetworks 112. The PSTN 108 may include circuit-switched telephonenetworks that provide plain old telephone service (POTS). The Internet110 may include a global system of interconnected computer networks anddevices that use common communication protocols, such as thetransmission control protocol (TCP), user datagram protocol (UDP) and/orthe internet protocol (IP) in the TCP/IP internet protocol suite. Thenetworks 112 may include wired and/or wireless communications networksowned and/or operated by other service providers. For example, thenetworks 112 may include another CN connected to one or more RANs, whichmay employ the same RAT as the RAN 104/113 or a different RAT.

Some or all of the WTRUs 102 a, 102 b, 102 c, 102 d in thecommunications system 100 may include multi-mode capabilities (e.g., theWTRUs 102 a, 102 b, 102 c, 102 d may include multiple transceivers forcommunicating with different wireless networks over different wirelesslinks). For example, the WTRU 102 c shown in FIG. 1A may be configuredto communicate with the base station 114 a, which may employ acellular-based radio technology, and with the base station 114 b, whichmay employ an IEEE 802 radio technology.

FIG. 1B is a system diagram illustrating an example WTRU 102. As shownin FIG. 1B, the WTRU 102 may include a processor 118, a transceiver 120,a transmit/receive element 122, a speaker/microphone 124, a keypad 126,a display/touchpad 128, non-removable memory 130, removable memory 132,a power source 134, a global positioning system (GPS) chipset 136,and/or other peripherals 138, among others. It will be appreciated thatthe WTRU 102 may include any sub-combination of the foregoing elementswhile remaining consistent with an embodiment.

The processor 118 may be a general purpose processor, a special purposeprocessor, a conventional processor, a digital signal processor (DSP), aplurality of microprocessors, one or more microprocessors in associationwith a DSP core, a controller, a microcontroller, Application SpecificIntegrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs)circuits, any other type of integrated circuit (IC), a state machine,and the like. The processor 118 may perform signal coding, dataprocessing, power control, input/output processing, and/or any otherfunctionality that enables the WTRU 102 to operate in a wirelessenvironment. The processor 118 may be coupled to the transceiver 120,which may be coupled to the transmit/receive element 122. While FIG. 1Bdepicts the processor 118 and the transceiver 120 as separatecomponents, it will be appreciated that the processor 118 and thetransceiver 120 may be integrated together in an electronic package orchip.

The transmit/receive element 122 may be configured to transmit signalsto, or receive signals from, a base station (e.g., the base station 114a) over the air interface 116. For example, in one embodiment, thetransmit/receive element 122 may be an antenna configured to transmitand/or receive RF signals. In an embodiment, the transmit/receiveelement 122 may be an emitter/detector configured to transmit and/orreceive IR, UV, or visible light signals, for example. In yet anotherembodiment, the transmit/receive element 122 may be configured totransmit and/or receive both RF and light signals. It will beappreciated that the transmit/receive element 122 may be configured totransmit and/or receive any combination of wireless signals.

Although the transmit/receive element 122 is depicted in FIG. 1B as asingle element, the WTRU 102 may include any number of transmit/receiveelements 122. More specifically, the WTRU 102 may employ MIMOtechnology. Thus, in one embodiment, the WTRU 102 may include two ormore transmit/receive elements 122 (e.g., multiple antennas) fortransmitting and receiving wireless signals over the air interface 116.

The transceiver 120 may be configured to modulate the signals that areto be transmitted by the transmit/receive element 122 and to demodulatethe signals that are received by the transmit/receive element 122. Asnoted above, the WTRU 102 may have multi-mode capabilities. Thus, thetransceiver 120 may include multiple transceivers for enabling the WTRU102 to communicate via multiple RATs, such as NR and IEEE 802.11, forexample.

The processor 118 of the WTRU 102 may be coupled to, and may receiveuser input data from, the speaker/microphone 124, the keypad 126, and/orthe display/touchpad 128 (e.g., a liquid crystal display (LCD) displayunit or organic light-emitting diode (OLED) display unit). The processor118 may also output user data to the speaker/microphone 124, the keypad126, and/or the display/touchpad 128. In addition, the processor 118 mayaccess information from, and store data in, any type of suitable memory,such as the non-removable memory 130 and/or the removable memory 132.The non-removable memory 130 may include random-access memory (RAM),read-only memory (ROM), a hard disk, or any other type of memory storagedevice. The removable memory 132 may include a subscriber identitymodule (SIM) card, a memory stick, a secure digital (SD) memory card,and the like. In other embodiments, the processor 118 may accessinformation from, and store data in, memory that is not physicallylocated on the WTRU 102, such as on a server or a home computer (notshown).

The processor 118 may receive power from the power source 134, and maybe configured to distribute and/or control the power to the othercomponents in the WTRU 102. The power source 134 may be any suitabledevice for powering the WTRU 102. For example, the power source 134 mayinclude one or more dry cell batteries (e.g., nickel-cadmium (NiCd),nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion),etc.), solar cells, fuel cells, and the like.

The processor 118 may also be coupled to the GPS chipset 136, which maybe configured to provide location information (e.g., longitude andlatitude) regarding the current location of the WTRU 102. In additionto, or in lieu of, the information from the GPS chipset 136, the WTRU102 may receive location information over the air interface 116 from abase station (e.g., base stations 114 a, 114 b) and/or determine itslocation based on the timing of the signals being received from two ormore nearby base stations. It will be appreciated that the WTRU 102 mayacquire location information by way of any suitablelocation-determination method while remaining consistent with anembodiment.

The processor 118 may further be coupled to other peripherals 138, whichmay include one or more software and/or hardware modules that provideadditional features, functionality and/or wired or wirelessconnectivity. For example, the peripherals 138 may include anaccelerometer, an e-compass, a satellite transceiver, a digital camera(for photographs and/or video), a universal serial bus (USB) port, avibration device, a television transceiver, a hands free headset, aBluetooth® module, a frequency modulated (FM) radio unit, a digitalmusic player, a media player, a video game player module, an Internetbrowser, a Virtual Reality and/or Augmented Reality (VR/AR) device, anactivity tracker, and the like. The peripherals 138 may include one ormore sensors, the sensors may be one or more of a gyroscope, anaccelerometer, a hall effect sensor, a magnetometer, an orientationsensor, a proximity sensor, a temperature sensor, a time sensor; ageolocation sensor; an altimeter, a light sensor, a touch sensor, amagnetometer, a barometer, a gesture sensor, a biometric sensor, and/ora humidity sensor.

The WTRU 102 may include a full duplex radio for which transmission andreception of some or all of the signals (e.g., associated withparticular subframes for both the UL (e.g., for transmission) anddownlink (e.g., for reception) may be concurrent and/or simultaneous.The full duplex radio may include an interference management unit 139 toreduce and or substantially eliminate self-interference via eitherhardware (e.g., a choke) or signal processing via a processor (e.g., aseparate processor (not shown) or via processor 118). In an embodiment,the WTRU 102 may include a half-duplex radio for which transmission andreception of some or all of the signals (e.g., associated withparticular subframes for either the UL (e.g., for transmission) or thedownlink (e.g., for reception)).

FIG. 10 is a system diagram illustrating the RAN 104 and the CN 106according to an embodiment. As noted above, the RAN 104 may employ anE-UTRA radio technology to communicate with the WTRUs 102 a, 102 b, 102c over the air interface 116. The RAN 104 may also be in communicationwith the CN 106.

The RAN 104 may include eNode-Bs 160 a, 160 b, 160 c, though it will beappreciated that the RAN 104 may include any number of eNode-Bs whileremaining consistent with an embodiment. The eNode-Bs 160 a, 160 b, 160c may each include one or more transceivers for communicating with theWTRUs 102 a, 102 b, 102 c over the air interface 116. In one embodiment,the eNode-Bs 160 a, 160 b, 160 c may implement MIMO technology. Thus,the eNode-B 160 a, for example, may use multiple antennas to transmitwireless signals to, and/or receive wireless signals from, the WTRU 102a.

Each of the eNode-Bs 160 a, 160 b, 160 c may be associated with aparticular cell (not shown) and may be configured to handle radioresource management decisions, handover decisions, scheduling of usersin the UL and/or DL, and the like. As shown in FIG. 10, the eNode-Bs 160a, 160 b, 160 c may communicate with one another over an X2 interface.

The CN 106 shown in FIG. 10 may include a mobility management entity(MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN)gateway (or PGW) 166. While each of the foregoing elements are depictedas part of the CN 106, it will be appreciated that any of these elementsmay be owned and/or operated by an entity other than the CN operator.

The MME 162 may be connected to each of the eNode-Bs 162 a, 162 b, 162 cin the RAN 104 via an S1 interface and may serve as a control node. Forexample, the MME 162 may be responsible for authenticating users of theWTRUs 102 a, 102 b, 102 c, bearer activation/deactivation, selecting aparticular serving gateway during an initial attach of the WTRUs 102 a,102 b, 102 c, and the like. The MME 162 may provide a control planefunction for switching between the RAN 104 and other RANs (not shown)that employ other radio technologies, such as GSM and/or WCDMA.

The SGW 164 may be connected to each of the eNode Bs 160 a, 160 b, 160 cin the RAN 104 via the S1 interface. The SGW 164 may generally route andforward user data packets to/from the WTRUs 102 a, 102 b, 102 c. The SGW164 may perform other functions, such as anchoring user planes duringinter-eNode B handovers, triggering paging when DL data is available forthe WTRUs 102 a, 102 b, 102 c, managing and storing contexts of theWTRUs 102 a, 102 b, 102 c, and the like.

The SGW 164 may be connected to the PGW 166, which may provide the WTRUs102 a, 102 b, 102 c with access to packet-switched networks, such as theInternet 110, to facilitate communications between the WTRUs 102 a, 102b, 102 c and IP-enabled devices.

The CN 106 may facilitate communications with other networks. Forexample, the CN 106 may provide the WTRUs 102 a, 102 b, 102 c withaccess to circuit-switched networks, such as the PSTN 108, to facilitatecommunications between the WTRUs 102 a, 102 b, 102 c and traditionalland-line communications devices. For example, the CN 106 may include,or may communicate with, an IP gateway (e.g., an IP multimedia subsystem(IMS) server) that serves as an interface between the CN 106 and thePSTN 108. In addition, the CN 106 may provide the WTRUs 102 a, 102 b,102 c with access to the other networks 112, which may include otherwired and/or wireless networks that are owned and/or operated by otherservice providers.

Although the WTRU is described in FIGS. 1A-1D as a wireless terminal, itis contemplated that in certain representative embodiments that such aterminal may use (e.g., temporarily or permanently) wired communicationinterfaces with the communication network.

In representative embodiments, the other network 112 may be a WLAN.

A WLAN in Infrastructure Basic Service Set (BSS) mode may have an AccessPoint (AP) for the BSS and one or more stations (STAs) associated withthe AP. The AP may have an access or an interface to a DistributionSystem (DS) or another type of wired/wireless network that carriestraffic in to and/or out of the BSS. Traffic to STAs that originatesfrom outside the BSS may arrive through the AP and may be delivered tothe STAs. Traffic originating from STAs to destinations outside the BSSmay be sent to the AP to be delivered to respective destinations.Traffic between STAs within the BSS may be sent through the AP, forexample, where the source STA may send traffic to the AP and the AP maydeliver the traffic to the destination STA. The traffic between STAswithin a BSS may be considered and/or referred to as peer-to-peertraffic. The peer-to-peer traffic may be sent between (e.g., directlybetween) the source and destination STAs with a direct link setup (DLS).In certain representative embodiments, the DLS may use an 802.11e DLS oran 802.11z tunneled DLS (TDLS). A WLAN using an Independent BSS (IBSS)mode may not have an AP, and the STAs (e.g., all of the STAs) within orusing the IBSS may communicate directly with each other. The IBSS modeof communication may sometimes be referred to herein as an “ad-hoc” modeof communication.

When using the 802.11ac infrastructure mode of operation or a similarmode of operations, the AP may transmit a beacon on a fixed channel,such as a primary channel. The primary channel may be a fixed width(e.g., 20 MHz wide bandwidth) or a dynamically set width via signaling.The primary channel may be the operating channel of the BSS and may beused by the STAs to establish a connection with the AP. In certainrepresentative embodiments, Carrier Sense Multiple Access with CollisionAvoidance (CSMA/CA) may be implemented, for example in in 802.11systems. For CSMA/CA, the STAs (e.g., every STA), including the AP, maysense the primary channel. If the primary channel is sensed/detectedand/or determined to be busy by a particular STA, the particular STA mayback off. One STA (e.g., only one station) may transmit at any giventime in a given BSS.

High Throughput (HT) STAs may use a 40 MHz wide channel forcommunication, for example, via a combination of the primary 20 MHzchannel with an adjacent or nonadjacent 20 MHz channel to form a 40 MHzwide channel.

Very High Throughput (VHT) STAs may support 20 MHz, 40 MHz, 80 MHz,and/or 160 MHz wide channels. The 40 MHz, and/or 80 MHz, channels may beformed by combining contiguous 20 MHz channels. A 160 MHz channel may beformed by combining 8 contiguous 20 MHz channels, or by combining twonon-contiguous 80 MHz channels, which may be referred to as an 80+80configuration. For the 80+80 configuration, the data, after channelencoding, may be passed through a segment parser that may divide thedata into two streams. Inverse Fast Fourier Transform (IFFT) processing,and time domain processing, may be done on each stream separately. Thestreams may be mapped on to the two 80 MHz channels, and the data may betransmitted by a transmitting STA. At the receiver of the receiving STA,the above described operation for the 80+80 configuration may bereversed, and the combined data may be sent to the Medium Access Control(MAC).

Sub 1 GHz modes of operation are supported by 802.11af and 802.11ah. Thechannel operating bandwidths, and carriers, are reduced in 802.11af and802.11ah relative to those used in 802.11n, and 802.11ac. 802.11afsupports 5 MHz, 10 MHz and 20 MHz bandwidths in the TV White Space(TVWS) spectrum, and 802.11ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and16 MHz bandwidths using non-TVWS spectrum. According to a representativeembodiment, 802.11ah may support Meter Type Control/Machine-TypeCommunications, such as MTC devices in a macro coverage area. MTCdevices may have certain capabilities, for example, limited capabilitiesincluding support for (e.g., only support for) certain and/or limitedbandwidths. The MTC devices may include a battery with a battery lifeabove a threshold (e.g., to maintain a very long battery life).

WLAN systems, which may support multiple channels, and channelbandwidths, such as 802.11n, 802.11ac, 802.11af, and 802.11ah, include achannel which may be designated as the primary channel. The primarychannel may have a bandwidth equal to the largest common operatingbandwidth supported by all STAs in the BSS. The bandwidth of the primarychannel may be set and/or limited by a STA, from among all STAs inoperating in a BSS, which supports the smallest bandwidth operatingmode. In the example of 802.11ah, the primary channel may be 1 MHz widefor STAs (e.g., MTC type devices) that support (e.g., only support) a 1MHz mode, even if the AP, and other STAs in the BSS support 2 MHz, 4MHz, 8 MHz, 16 MHz, and/or other channel bandwidth operating modes.Carrier sensing and/or Network Allocation Vector (NAV) settings maydepend on the status of the primary channel. If the primary channel isbusy, for example, due to a STA (which supports only a 1 MHz operatingmode), transmitting to the AP, the entire available frequency bands maybe considered busy even though a majority of the frequency bands remainsidle and may be available.

In the United States, the available frequency bands, which may be usedby 802.11ah, are from 902 MHz to 928 MHz. In Korea, the availablefrequency bands are from 917.5 MHz to 923.5 MHz. In Japan, the availablefrequency bands are from 916.5 MHz to 927.5 MHz. The total bandwidthavailable for 802.11ah is 6 MHz to 26 MHz depending on the country code.

FIG. 1D is a system diagram illustrating the RAN 113 and the CN 115according to an embodiment. As noted above, the RAN 113 may employ an NRradio technology to communicate with the WTRUs 102 a, 102 b, 102 c overthe air interface 116. The RAN 113 may also be in communication with theCN 115.

The RAN 113 may include gNBs 180 a, 180 b, 180 c, though it will beappreciated that the RAN 113 may include any number of gNBs whileremaining consistent with an embodiment. The gNBs 180 a, 180 b, 180 cmay each include one or more transceivers for communicating with theWTRUs 102 a, 102 b, 102 c over the air interface 116. In one embodiment,the gNBs 180 a, 180 b, 180 c may implement MIMO technology. For example,gNBs 180 a, 108 b may utilize beamforming to transmit signals to and/orreceive signals from the gNBs 180 a, 180 b, 180 c. Thus, the gNB 180 a,for example, may use multiple antennas to transmit wireless signals to,and/or receive wireless signals from, the WTRU 102 a. In an embodiment,the gNBs 180 a, 180 b, 180 c may implement carrier aggregationtechnology. For example, the gNB 180 a may transmit multiple componentcarriers to the WTRU 102 a (not shown). A subset of these componentcarriers may be on unlicensed spectrum while the remaining componentcarriers may be on licensed spectrum. In an embodiment, the gNBs 180 a,180 b, 180 c may implement Coordinated Multi-Point (CoMP) technology.For example, WTRU 102 a may receive coordinated transmissions from gNB180 a and gNB 180 b (and/or gNB 180 c).

The WTRUs 102 a, 102 b, 102 c may communicate with gNBs 180 a, 180 b,180 c using transmissions associated with a scalable numerology. Forexample, the OFDM symbol spacing and/or OFDM subcarrier spacing may varyfor different transmissions, different cells, and/or different portionsof the wireless transmission spectrum. The WTRUs 102 a, 102 b, 102 c maycommunicate with gNBs 180 a, 180 b, 180 c using subframe or transmissiontime intervals (TTIs) of various or scalable lengths (e.g., containingvarying number of OFDM symbols and/or lasting varying lengths ofabsolute time).

The gNBs 180 a, 180 b, 180 c may be configured to communicate with theWTRUs 102 a, 102 b, 102 c in a standalone configuration and/or anon-standalone configuration. In the standalone configuration, WTRUs 102a, 102 b, 102 c may communicate with gNBs 180 a, 180 b, 180 c withoutalso accessing other RANs (e.g., such as eNode-Bs 160 a, 160 b, 160 c).In the standalone configuration, WTRUs 102 a, 102 b, 102 c may utilizeone or more of gNBs 180 a, 180 b, 180 c as a mobility anchor point. Inthe standalone configuration, WTRUs 102 a, 102 b, 102 c may communicatewith gNBs 180 a, 180 b, 180 c using signals in an unlicensed band. In anon-standalone configuration WTRUs 102 a, 102 b, 102 c may communicatewith/connect to gNBs 180 a, 180 b, 180 c while also communicatingwith/connecting to another RAN such as eNode-Bs 160 a, 160 b, 160 c. Forexample, WTRUs 102 a, 102 b, 102 c may implement DC principles tocommunicate with one or more gNBs 180 a, 180 b, 180 c and one or moreeNode-Bs 160 a, 160 b, 160 c substantially simultaneously. In thenon-standalone configuration, eNode-Bs 160 a, 160 b, 160 c may serve asa mobility anchor for WTRUs 102 a, 102 b, 102 c and gNBs 180 a, 180 b,180 c may provide additional coverage and/or throughput for servicingWTRUs 102 a, 102 b, 102 c.

Each of the gNBs 180 a, 180 b, 180 c may be associated with a particularcell (not shown) and may be configured to handle radio resourcemanagement decisions, handover decisions, scheduling of users in the ULand/or DL, support of network slicing, dual connectivity, interworkingbetween NR and E-UTRA, routing of user plane data towards User PlaneFunction (UPF) 184 a, 184 b, routing of control plane informationtowards Access and Mobility Management Function (AMF) 182 a, 182 b andthe like. As shown in FIG. 1D, the gNBs 180 a, 180 b, 180 c maycommunicate with one another over an Xn interface.

The CN 115 shown in FIG. 1D may include at least one AMF 182 a, 182 b,at least one UPF 184 a, 184 b, at least one Session Management Function(SMF) 183 a, 183 b, and possibly a Data Network (DN) 185 a, 185 b. Whileeach of the foregoing elements are depicted as part of the CN 115, itwill be appreciated that any of these elements may be owned and/oroperated by an entity other than the CN operator.

The AMF 182 a, 182 b may be connected to one or more of the gNBs 180 a,180 b, 180 c in the RAN 113 via an N2 interface and may serve as acontrol node. For example, the AMF 182 a, 182 b may be responsible forauthenticating users of the WTRUs 102 a, 102 b, 102 c, support fornetwork slicing (e.g., handling of different PDU sessions with differentrequirements), selecting a particular SMF 183 a, 183 b, management ofthe registration area, termination of NAS signaling, mobilitymanagement, and the like. Network slicing may be used by the AMF 182 a,182 b in order to customize CN support for WTRUs 102 a, 102 b, 102 cbased on the types of services being utilized WTRUs 102 a, 102 b, 102 c.For example, different network slices may be established for differentuse cases such as services relying on ultra-reliable low latency (URLLC)access, services relying on enhanced massive mobile broadband (eMBB)access, services for machine type communication (MTC) access, and/or thelike. The AMF 162 may provide a control plane function for switchingbetween the RAN 113 and other RANs (not shown) that employ other radiotechnologies, such as LTE, LTE-A, LTE-A Pro, and/or non-3GPP accesstechnologies such as WiFi.

The SMF 183 a, 183 b may be connected to an AMF 182 a, 182 b in the CN115 via an N11 interface. The SMF 183 a, 183 b may also be connected toa UPF 184 a, 184 b in the CN 115 via an N4 interface. The SMF 183 a, 183b may select and control the UPF 184 a, 184 b and configure the routingof traffic through the UPF 184 a, 184 b. The SMF 183 a, 183 b mayperform other functions, such as managing and allocating UE IP address,managing PDU sessions, controlling policy enforcement and QoS, providingdownlink data notifications, and the like. A PDU session type may beIP-based, non-IP based, Ethernet-based, and the like.

The UPF 184 a, 184 b may be connected to one or more of the gNBs 180 a,180 b, 180 c in the RAN 113 via an N3 interface, which may provide theWTRUs 102 a, 102 b, 102 c with access to packet-switched networks, suchas the Internet 110, to facilitate communications between the WTRUs 102a, 102 b, 102 c and IP-enabled devices. The UPF 184, 184 b may performother functions, such as routing and forwarding packets, enforcing userplane policies, supporting multi-homed PDU sessions, handling user planeQoS, buffering downlink packets, providing mobility anchoring, and thelike.

The CN 115 may facilitate communications with other networks. Forexample, the CN 115 may include, or may communicate with, an IP gateway(e.g., an IP multimedia subsystem (IMS) server) that serves as aninterface between the CN 115 and the PSTN 108. In addition, the CN 115may provide the WTRUs 102 a, 102 b, 102 c with access to the othernetworks 112, which may include other wired and/or wireless networksthat are owned and/or operated by other service providers. In oneembodiment, the WTRUs 102 a, 102 b, 102 c may be connected to a localData Network (DN) 185 a, 185 b through the UPF 184 a, 184 b via the N3interface to the UPF 184 a, 184 b and an N6 interface between the UPF184 a, 184 b and the DN 185 a, 185 b.

In view of FIGS. 1A-1D, and the corresponding description of FIGS.1A-1D, one or more, or all, of the functions described herein withregard to one or more of: WTRU 102 a-d, Base Station 114 a-b, eNode-B160 a-c, MME 162, SGW 164, PGW 166, gNB 180 a-c, AMF 182 a-ab, UPF 184a-b, SMF 183 a-b, DN 185 a-b, and/or any other device(s) describedherein, may be performed by one or more emulation devices (not shown).The emulation devices may be one or more devices configured to emulateone or more, or all, of the functions described herein. For example, theemulation devices may be used to test other devices and/or to simulatenetwork and/or WTRU functions.

The emulation devices may be designed to implement one or more tests ofother devices in a lab environment and/or in an operator networkenvironment. For example, the one or more emulation devices may performthe one or more, or all, functions while being fully or partiallyimplemented and/or deployed as part of a wired and/or wirelesscommunication network in order to test other devices within thecommunication network. The one or more emulation devices may perform theone or more, or all, functions while being temporarilyimplemented/deployed as part of a wired and/or wireless communicationnetwork. The emulation device may be directly coupled to another devicefor purposes of testing and/or may performing testing using over-the-airwireless communications.

The one or more emulation devices may perform the one or more, includingall, functions while not being implemented/deployed as part of a wiredand/or wireless communication network. For example, the emulationdevices may be utilized in a testing scenario in a testing laboratoryand/or a non-deployed (e.g., testing) wired and/or wirelesscommunication network in order to implement testing of one or morecomponents. The one or more emulation devices may be test equipment.Direct RF coupling and/or wireless communications via RF circuitry(e.g., which may include one or more antennas) may be used by theemulation devices to transmit and/or receive data.

A WLAN in infrastructure Basic Service Set (BSS) mode may have an AccessPoint (AP/PCP) for the BSS and one or more STAs or WTRUs associated withthe AP/PCP. The AP/PCP may have access and/or an interface to aDistribution System (DS) or another type of wired/wireless network thatcarries traffic in and out of the BSS. Traffic to STAs that originatesfrom outside the BSS may arrive through the AP/PCP and is delivered tothe STAs. Traffic originating from STAs to destinations outside the BSSmay be sent to the AP/PCP to be delivered to the respectivedestinations. Traffic between STAs within the BSS may also be sentthrough the AP/PCP where the source STA sends traffic to the AP/PCP andthe AP/PCP delivers the traffic to the destination STA. Such trafficbetween STAs within a BSS is, in effect, peer-to-peer traffic. Suchpeer-to-peer traffic may also be sent directly between the source anddestination STAs with a direct link setup (DLS) using an 802.11e DLS oran 802.11z tunneled DLS (TDLS). A WLAN using an Independent BSS (IBSS)mode may have no AP/PCP, and/or STAs, communicating directly with eachother. This mode of communication is referred to as an “ad-hoc” mode ofcommunication.

Using the 802.11ac infrastructure mode of operation, an AP/PCP maytransmit a beacon on a fixed channel, usually the primary channel. Thischannel may be 20 MHz wide, and may be the operating channel of the BSS.This channel may also be used by the STAs to establish a connection withthe AP/PCP. In a given mode of operation, the fundamental channel accessmechanism in an 802.11 system is Carrier Sense Multiple Access withCollision Avoidance (CSMA/CA). In this mode of operation, every STA,including the AP/PCP, will sense the primary channel. If the channel isdetected to be busy, the STA may back off such that only one STA maytransmit at any given time in a given BSS.

In 802.11n, High Throughput (HT) STAs may use a 40 MHz wide channel forcommunication. This may be achieved by combining a primary 20 MHzchannel with an adjacent 20 MHz channel to form a 40 MHz wide contiguouschannel.

In 802.11ac, Very High Throughput (VHT) STAs may support 20 MHz, 40 MHz,80 MHz, and 160 MHz wide channels. The 40 MHz, and 80 MHz, channels maybe formed by combining contiguous 20 MHz channels similar to 802.11ndescribed above. A 160 MHz channel may be formed either by combining 8contiguous 20 MHz channels, or by combining two non-contiguous 80 MHzchannels, this may also be referred to as an 80+80 configuration. For an80+80 configuration, the data, after channel encoding, may be passedthrough a segment parser that divides the channel encoded data into twostreams. IFFT and time domain processing may be done on each streamseparately. The streams may then be mapped on to the two channels, andthe data may be transmitted. At the receiver, this mechanism may bereversed, and the combined data is sent to the MAC.

Sub 1 GHz modes of operation may be supported by 802.11af, and 802.11ah.For these specifications, the channel operating bandwidths and carriersmay be reduced relative to those used in 802.11n and 802.11ac. 802.11afsupports 5 MHz, 10 MHz and 20 MHz bandwidths in the TV White Space(TVWS) spectrum, and 802.11ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and16 MHz bandwidths using non-TVWS spectrum. A possible application for802.11ah may be to Meter Type Control (MTC) devices in a macro coveragearea. MTC devices may have limited capabilities including only supportfor limited bandwidths, but may also require a very long battery life.

WLAN systems which support multiple channels and channel widths, such as802.11n, 802.11ac, 802.11af, and 802.11ah, may include a channel whichis designated as the primary channel. The primary channel may have abandwidth equal to the largest common operating bandwidth supported byall STAs in the BSS. The bandwidth of the primary channel may thereforebe limited by the STA, from all operational STAs in a BSS, whichsupports the smallest bandwidth operating mode. In the example of802.11ah, the primary channel may be 1 MHz wide if there is anoperational STA (e.g. MTC type devices) that only support a 1 MHz modeeven if the AP/PCP and other STAs in the BSS may support larger channelbandwidth operating modes. All carrier sensing and network allocationvector (NAV) settings may depend on the status of the primary channel.If the primary channel is busy, for example, due to an STA supportingonly a 1 MHz operating mode transmitting to the AP/PCP, then the entireavailable frequency bands are considered busy even though majority of itstays idle and available.

802.11ac may improve spectral efficiency by using downlink Multi-UserMIMO (MU-MIMO) transmission to multiple STA's in the same symbol's timeframe, for example, during a downlink OFDM symbol. The potential for theuse of downlink MU-MIMO may also be used with 802.11ah. It will be notedthat since downlink MU-MIMO, as used in 802.11ac, uses the same symboltiming to multiple STA's, interference of the waveform transmissions tomultiple STA's is not an issue. However, all STA's involved in MU-MIMOtransmission with the AP/PCP should use the same channel or band, whichmay limit the operating bandwidth to the smallest channel bandwidth thatis supported by the STA's that are included in the MU-MIMO transmissionwith the AP/PCP.

802.11ad is an amendment to the WLAN standard and specifies the mediumaccess control (MAC) and physical (PHY) layers for VHT implementationsin the 60 GHz band. 802.11ad may support data rates up to 7 Gbits/s.802.11ad may also support three different modulation modes includingcontrol PHY with single carrier and spread spectrum, single carrier PHY,and OFDM PHY.

802.11ad may also use 60 GHz unlicensed band, which is availableglobally. At 60 GHz, the wavelength is 5 mm, which makes compact andantenna or antenna arrays possible. Such an antenna can create narrow RFbeams at both transmitter and receiver, which effectively increases thecoverage range and reduces the interference.

802.11ad may also support a frame structure that facilitates a mechanismfor beamforming sounding such as discovery and tracking. A beamformingsounding protocol may include two components including a sector levelsweep (SLS) procedure and a beam refinement protocol (BRP) procedure.The SLS procedure is used for transmit beamforming sounding and the BRPprocedure enables receive beamforming sounding and iterative refinementof transmit and receive beams. As used herein, where applicable, theterm beamforming may correspond to beamforming sounding.

MIMO transmissions, including both SU-MIMO and MU-MIMO, may not besupported by 802.11ad.

As shown in FIG. 2, 802.11ad may support three physical layerconvenience procedure (PLOP) protocol data unit (PPDU) formats includingControl PHY 210, Single Carrier (SC) PHY 220, and OFDM PHY PPDUs 230.

Control PHY 210 is defined in 802.11ad as the lowest data ratetransmission and may include a short training field (STF) 211 and achannel estimation field (CEF) 212 via a π/2-BPSK 213. As referencedherein, BPSK corresponds to binary phase-shift keying, DBPSK correspondsto a differential BPSK, QPSK corresponds to quadrature phase-shiftkeying, and QAM corresponds to quadrature amplitude modulation. TheControl PHY 210 may also include a header 214 and data 215 via aπ/2-DBPSK 216 as well as a beamforming training (TRN-T/R) component 217when applicable. Frames transmitted before beamforming training may useControl PHY PPDU.

As shown in FIG. 2, single carrier (SC) 220 may include an STF 221, aCEF 222 and a header 223 via a π/2-BPSK 224, a data block 225 via aπ/2-BPSK/QPSK/16QAM 226, and beamforming training (TRN-T/R) component227, when applicable. The orthogonal frequency division multiplexing(OFDM) 230 may include a STF 231 and CEF 232 via a π/2-BPSK 233. TheOFDM 230 may also include a header 234 via a QPSK-OFDM, a data block 236via a SQPSK/QSPK/16QAM/64QAM 231, and beamforming training (TRN-T/R)component 238, when applicable.

A transmission diagram of Control PHY, as applied in 802.11ad, isprovided in FIG. 3. As shown, the control PHY PPDU 300 transmission mayinclude a scrambler 310, a Low Density Parity Check (LDPC) Encoder 320,a differential Encoder 330, spreading (e.g., at 32×) 340, and π/2-BPSKmodulation 350.

An example sector level sweep (SLS) 400 sounding procedure is shown inFIG. 4. Note that the terms training and sounding are usedinterchangeably herein. As shown, the SLS 400 may include an initiator410 conducting an initiator sector sweep (ISS) and transmitting SSframes 412 to a responder 420. The responder 420 may conduct a respondersector sweep (RSS) 421 and transmit SS frames 413 to the initiator 410.The initiator 410 may provide SS feedback 414 and the responder 420 mayprovide a synchronization signal (SS) acknowledgement 415. A beamrefinement process 440 may follow the SLS 400.

FIG. 5 shows a diagram of an example sector sweep (SSW) frame format 500when a SSW frame may be transmitted using control PHY. As shown, the SSWframe format 500 may include a frame control 510 for two octets, aduration 511 for two octets, a receiver address (RA) 512 for six octets,a transmitter address (TA) 513 for six octets, SSW frames 514 for threeoctets, SSW feedback 515 for three octets, and frame check sequence(FCS) 516 for four octets. SLS sounding may be performed using Beaconframes or SSW frames. When Beacon frames are utilized, an AP may repeatthe Beacon frame with multiple beams/sectors within each Beacon interval(BI) and multiple STAs may perform beamforming sounding simultaneously.However, based on the size of the beamforming sounding, the AP may notsweep all the sectors/beams within one BI. Thus, an STA may waitmultiple BIs to complete ISS sounding, which may cause latency. An SSWframe may be utilized for point-to-point beamforming sounding.

FIG. 6 shows a diagram of an example of the SSW field 514 of FIG. 5. Asshown, the field may contain 24 bits where the first bit b0 correspondsto the direction 601, the next nine bits correspond to the countdown(CDOWN) 602, the next 6 bits correspond to a sector ID 603, the next twobits correspond to a directional multi-gigabit (DMG) Antenna ID 604, andthe last six bits correspond to the receive sector sweep (RXSS) Length605.

FIG. 7A shows a diagram of an example SSW feedback field format whentransmitted as a part of ISS 701. As shown, the field may contain 24bits where the first nine bits correspond to a the total sectors in ISS710, the next two bits correspond to the number of RX DMG antennas 711,the next five bits are reserved bits 712, the next bit is a pollrequired bit 713 and the last seven bits are reserved bits 714.

FIG. 7B shows a diagram of an example of SSW feedback field format whennot transmitted as part of the ISS 702. As shown, the field may contain24 bits where the first six bits correspond to a sector select 720, thenext two bits correspond to a DMG antenna select 721, the next eightbits correspond to SNR Report bits 722, the next bit is a poll requiredbit 723 and the last seven bits are reserved bits 724.

FIG. 8 shows a diagram of an example of beam reinforcement protocol(BRP) TRN-RX packet 800. During beam reinforcement, an STA may improveits antenna configuration, such as its antenna weight vectors, fortransmission and reception. During a beam refinement procedure, BRPpackets may be used to train the receiver and transmitter antenna. Theremay be two types of BRP packets: BRP-RX packets and BRP-TX packets. Asshown in FIG. 8, a BRP TRN-RX packet may include a PLOP Header 810, aBRP MAC body 820, AGC automatic gain control (AGC) field 830, and BRPsounding (5N) TRN-RX field 840. A BRP packet 800 may be carried by a DMGPPDU followed by a training field containing the AGC field 830 and atransmitter or receiver training field 840, as shown in FIG. 8.

A value of N in FIG. 8 may be a training length given in the PLOP header810, which indicates that the AGC 830 has 4N subfields and that theTRN-RX field 840 has 5N subfields. The channel estimation (CE) subfieldwithin the subfields 841 of TRN-RX field 840 may be the same as orsimilar to the CEF 212 of the Control PHY 210 of FIG. 2. All subfields841 in the BRP TRN-RX field 840 may be transmitted using rotatedπ/2-BPSK modulation. All subfields 831 and 832 of the AGC 830 may beGb64 such that the OFDM/SC subfields and Control subfields are all Gb64.

The BRP MAC frame 820 may be an action No ACK frame, which may includeone or more of a category field, an unprotected DMG action field, adialog Token field, a BRP request field, a DMG Beam Refinement element,and/or Channel Measurement Feedback element 1 . . . k fields.

Task Group ay (TGay) may define standardized modifications to both theIEEE 802.11 PHY and MAC and may enable at least one mode of operationcapable of supporting a maximum throughput of at least 20 gigabits persecond measured at the MAC data service access point, while maintainingor improving the power efficiency per station. The amendment may alsodefine operations for license-exempt bands above 45 GHz while ensuringbackward compatibility and coexistence with legacy directionalmulti-gigabit stations, such as those in the IEEE 802.11ad-2012amendment, operating in the same band. Such an amendment may achievehigher maximum throughput as well as mobility and outdoor support.

802.11 ay may operate in the same band as legacy standards and,accordingly, backward compatibility and coexistence with legacies in thesame band may be provided.

FIG. 9 shows a diagram of an example of an 802.11ay PPDU format.802.11ay PPDU may contain a legacy part and an enhanced directionalmulti-gigabit (EDMG) part. The legacy-short training field (L-STF) 910,legacy-channel estimation field (L-CEF) 920, legacy-header (L-Header)930, and EDMG-Header-A 940 fields may be transmitted using SC mode forbackward compatibility. For a control mode PPDU, the reserved bits 22and 23 may be both set to an affirmative value, such as 1, to indicatethe presence of the EDMG-Header-A field 940. For a SC mode PPDU or anOFDM mode PPDU, the reserved bit 46 may be set to an affirmative value,such as 1, to indicate the presence of the EDMG-Header-A field 940. The802.11ay PPDU format may also contain an EDMG-CEF field 960, a EDMGHeader-B 970, a data field 980, an AGC 990 and a TRN field 995.

802.11ad+/802.11ay may include and/or utilize methods including spatialdiversity with beam switching, diversity with a single beam, weightedmultipath beamforming sounding, beam division multiple access, singleuser spatial multiplexing, and/or reduced beamforming sounding overhead.According to an implementation, all physical antennas (PA) may beexcited by all the weights, as shown in FIG. 10. According to anotherimplementation, different PAs may be excited by separate weights, asshown in FIG. 11.

As shown in FIG. 10, a signal may be input into transmitter 1001'scoding/modulation components 1010. The signal may be converted at thetransmitter 1001's digital to analog (DAC)/Up-converters 1012 and may bepassed through weights 1015 controlled via a digital controller 1014such that all the transmit antennas 1016 are excited by all the weights1015 a-1115 d. A receiver 1002 may receive the transmitted signal viareceive antennas 1021 and the signal may be passed through weights 1022controlled via a digital controller 1023 and converted via ADC/Downconverters 1024 and may be decoded and/or demodulated viadecoding/demodulation components 1025.

As shown in FIG. 11, a signal may be input into transmitter 1101'scoding/modulation components 1110. The signal may converted at thetransmitter 1101's DAC/Up-converters 1111 and may be passed throughweights 1113 controlled via a digital controller 1112 such that all thetransmit antennas 1114 may be excited by separate weights 1113 a-1113 d.A receiver 1102 may receive the transmitted signal via receive antennas1120 and the signal may be passed through weights 1121 controlled via adigital controller 1122 and converted via ADC/Down converters 1123 andmay be decoded and/or demodulated via decoding/demodulation components1124.

802.11ay may also have EDMG CEF sequences. The EDMG OFDM PHY may use thepairs of Seq^(iSTS) _(left,N) and Seq^(iSTS) _(right,N) sequences,i_(STS)=1, 2, . . . , 8, of length N=176 to generate EDMG-CEF fields infrequency domain for single channel. Three DC tones may also be includedbetween left and right sequences. Table 1 below shows an example of EDMGCEF sequences.

TABLE 1 EDMG CEF Sequences The Sequence Seq¹ _(left, 176)(k), to betransmitted from left to right, up to down −1 −j −j +1 +j −j +1 −1 +1 −j−1 +1 −1 +1 −j −1 −1 +j +j +j −1 −1 +1 +j +j −1 −j +j −1 +1 −1 +j +1 +1−1 +1 −j −1 −1 +j +j +j −1 −1 +j −1 −1 −j +1 −1 −j +j −j −1 +j −j +j −j−1 +j +j +1 +1 +1 +j +j +j −1 −1 −j +1 −1 −j +j −j −1 +j +j −j +j +1 −j−j −1 −1 −1 −j −j +j −1 −1 −j +1 −1 −j +j −j −1 +j −j +j −j −1 +j +j +1+1 +1 +j +j −j +1 +1 +j −1 +1 +j −j +j +1 −j −j +j −j −1 +j +j +1 +1 +1+j +j −1 −j −j +1 +j −j +1 −1 +1 −j −1 +1 −1 +1 −j −1 −1 +j +j +j −1 −1−1 −j −j +1 +j −j +1 −1 +1 −j −1 −1 +1 −1 +j +1 +1 −j −j −j +1 +1 TheSequence Seq² _(left, 176)(k), to be transmitted from left to right, upto down +j −1 −1 −j +1 −1 −j +j −j −1 +j +1 −1 +1 −j −1 −1 +j +j +j −1−1 +j −1 −1 −j +1 −1 −j +j −j −1 +j −1 +1 −1 +j +1 +1 −j −j −j +1 +1 −1−j −j +1 +j −j +1 −1 +1 −j −1 +j −j +j +1 −j −j −1 −1 −1 −j −j +1 +j +j−1 −j +j −1 +1 −1 +j +1 +j −j +j +1 −j −j −1 −1 −1 −j −j +1 +j +j −1 −j+j −1 +1 −1 +j +1 −j +j −j −1 +j +j +1 +1 +1 +j +j +1 +j +j −1 −j +j −1+1 −1 +j +1 +j −j +j +1 −j −j −1 −1 −1 −j −j −j +1 +1 +j −1 +1 +j −j +j+1 −j −1 +1 −1 +j +1 +1 −j −j −j +1 +1 +j −1 −1 −j +1 −1 −j +j −j −1 +j−1 +1 −1 +j +1 +1 −j −j −j +1 +1 The Sequence Seq³ _(left, 176)(k), tobe transmitted from left to right, up to down −1 −j −j +1 +j −j +1 −1 +1−j −1 +1 −1 +1 −j −1 −1 +j +j +j −1 −1 −j +1 +1 +j −1 +1 +j −j +j +1 −j−j +j −j −1 +j +j +1 +1 +1 +j +j −1 −j −j +1 +j −j +1 −1 +1 −j −1 +1 −1+1 −j −1 −1 +j +j +j −1 −1 +j −1 −1 −j +1 −1 −j +j −j −1 +j +j −j +j +1−j −j −1 −1 −1 −j −j +j −1 −1 −j +1 −1 −j +j −j −1 +j −j +j −j −1 +j +j+1 +1 +1 +j +j −1 −j −j +1 +j −j +1 −1 +1 −j −1 −1 +1 −1 +j +1 +1 −j −j−j +1 +1 −j +1 +1 +j −1 +1 +j −j +j +1 −j +j −j +j +1 −j −j −1 −1 −1 −j−j −1 −j −j +1 +j −j +1 −1 +1 −j −1 −1 +1 −1 +j +1 +1 −j −j −j +1 +1 TheSequence Seq⁴ _(left, 176)(k), to be transmitted from left to right, upto down −j +1 +1 +j −1 +1 +j −j +j +1 −j −j +j −j −1 +j +j +1 +1 +1 +j+j −j +1 +1 +j −1 +1 +j −j +j +1 −j +j −j +j +1 −j −j −1 −1 −1 −j −j +j−1 −1 −j +1 −1 −j +j −j −1 +j +j −j +j +1 −j −j −1 −1 −1 −j −j −j +1 +1+j −1 +1 +j −j +j +1 −j +j −j +j +1 −j −j −1 −1 −1 −j −j −1 −j −j +1 +j−j +1 −1 +1 −j −1 −1 +1 −1 +j +1 +1 −j −j −j +1 +1 −1 −j −j +1 +j −j +1−1 +1 −j −1 +1 −1 +1 −j −1 −1 +j +j +j −1 −1 −1 −j −j +1 +j −j +1 −1 +1−j −1 −1 +1 −1 +j +1 +1 −j −j −j +1 +1 +1 +j +j −1 −j +j −1 +1 −1 +j +1−1 +1 −1 +j +1 +1 −j −j −j +1 +1 The Sequence Seq⁵ _(left, 176)(k), tobe transmitted from left to right, up to down −1 −j −j +1 +j −j +1 −1 +1−j −1 +1 −1 +1 −j −1 −1 +j +j +j −1 −1 +j −1 −1 −j +1 −1 −j +j −j −1 +j+j −j +j +1 −j −j −1 −1 −1 −j −j +1 +j +j −1 −j +j −1 +1 −1 +j +1 −1 +1−1 +j +1 +1 −j −j −j +1 +1 +j −1 −1 −j +1 −1 −j +j −j −1 +j +j −j +j +1−j −j −1 −1 −1 −j −j +j −1 −1 −j +1 −1 −j +j −j −1 +j −j +j −j −1 +j +j+1 +1 +1 +j +j +1 +j +j −1 −j +j −1 +1 −1 +j +1 +1 −1 +1 −j −1 −1 +j +j+j −1 −1 +j −1 −1 −j +1 −1 −j +j −j −1 +j −j +j −j −1 +j +j +1 +1 +1 +j+j −1 −j −j +1 +j −j +1 −1 +1 −j −1 −1 +1 −1 +j +1 +1 −j −j −j +1 +1 TheSequence Seq⁶ _(left, 176)(k), to be transmitted from left to right, upto down −1 −j −j +1 +j −j +1 −1 +1 −j −1 −1 +1 −1 +j +1 +1 −j −j −j +1+1 +j −1 −1 −j +1 −1 −j +j −j −1 +j −j +j −j −1 +j +j +1 +1 +1 +j +j −1−j −j +1 +j −j +1 −1 +1 −j −1 −1 +1 −1 +j +1 +1 −j −j −j +1 +1 −j +1 +1+j −1 +1 +j −j +j +1 −j +j −j +j +1 −j −j −1 −1 −1 −j −j +j −1 −1 −j +1−1 −j +j −j −1 +j +j −j +j +1 −j −j −1 −1 −1 −j −j +1 +j +j −1 −j +j −1+1 −1 +j +1 −1 +1 −1 +j +1 +1 −j −j −j +1 +1 −j +1 +1 +j −1 +1 +j −j +j+1 −j −j +j −j −1 +j +j +1 +1 +1 +j +j +1 +j +j −1 −j +j −1 +1 −1 +j +1−1 +1 −1 +j +1 +1 −j −j −j +1 +1 The Sequence Seq⁷ _(left, 176)(k), tobe transmitted from left to right, up to down −1 −j −j +1 +j −j +1 −1 +1−j −1 −j +j −j −1 +j +j +1 +1 +1 +j +j −j +1 +1 +j −1 +1 +j −j +j +1 −j−1 +1 −1 +j +1 +1 −j −j −j +1 +1 −j +1 +1 +j −1 +1 +j −j +j +1 −j +1 −1+1 −j −1 −1 +j +j +j −1 −1 −1 −j −j +1 +j −j +1 −1 +1 −j −1 +j −j +j +1−j −j −1 −1 −1 −j −j +j −1 −1 −j +1 −1 −j +j −j −1 +j −1 +1 −1 +j +1 +1−j −j −j +1 +1 −1 −j −j +1 +j −j +1 −1 +1 −j −1 +j −j +j +1 −j −j −1 −1−1 −j −j +1 +j +j −1 −j +j −1 +1 −1 +j +1 +j −j +j +1 −j −j −1 −1 −1 −j−j −j +1 +1 +j −1 +1 +j −j +j +1 −j −1 +1 −1 +j +1 +1 −j −j −j +1 +1 TheSequence Seq⁸ _(left, 176)(k), to be transmitted from left to right, upto down +1 +j +j −1 −j +j −1 +1 −1 +j +1 −1 +1 −1 +j +1 +1 −j −j −j +1+1 +1 +j +j −1 −j +j −1 +1 −1 +j +1 +1 −1 +1 −j −1 −1 +j +j +j −1 −1 −j+1 +1 +j −1 +1 +j −j +j +1 −j +j −j +j +1 −j −j −1 −1 −1 −j −j +j −1 −1−j +1 −1 −j +j −j −1 +j +j −j +j +1 −j −j −1 −1 −1 −j −j −j +1 +1 +j −1+1 +j −j +j +1 −j +j −j +j +1 −j −j −1 −1 −1 −j −j −j +1 +1 +j −1 +1 +j−j +j +1 −j −j +j −j −1 +j +j +1 +1 +1 +j +j +1 +j +j −1 −j +j −1 +1 −1+j +1 −1 +1 −1 +j +1 +1 −j −j −j +1 +1 −1 −j −j +1 +j −j +1 −1 +1 −j −1−1 +1 −1 +j +1 +1 −j −j −j +1 +1 The Sequence Seq¹ _(right, 176)(k), tobe transmitted from left to right, up to down −1 −j −j +1 +j −j +1 −1 +1−j −1 +1 −1 +1 −j −1 −1 +j +j +j −1 −1 +1 +j +j −1 −j +j −1 +1 −1 +j +1+1 −1 +1 −j −1 −1 +j +j +j −1 −1 +j −1 −1 −j +1 −1 −j +j −j −1 +j −j +j−j −1 +j +j +1 +1 +1 +j +j +j −1 −1 −j +1 −1 −j +j −j −1 +j +j −j +j +1−j −j −1 −1 −1 −j −j −j +1 +1 +j −1 +1 +j −j +j +1 −j +j −j +j +1 −j −j−1 −1 −1 −j −j +j −1 −1 −j +1 −1 −j +j −j −1 +j +j −j +j +1 −j −j −1 −1−1 −j −j +1 +j +j −1 −j +j −1 +1 −1 +j +1 −1 +1 −1 +j +1 +1 −j −j −j +1+1 +1 +j +j −1 −j +j −1 +1 −1 +j +1 +1 −1 +1 −j −1 −1 +j +j +j −1 −1 TheSequence Seq² _(right, 176)(k), to be transmitted from left to right, upto down +j −1 −1 −j +1 −1 −j +j −j −1 +j +1 −1 +1 −j −1 −1 +j +j +j −1−1 +j −1 −1 −j +1 −1 −j +j −j −1 +j −1 +1 −1 +j +1 +1 −j −j −j +1 +1 −1−j −j +1 +j −j +1 −1 +1 −j −1 +j −j +j +1 −j −j −1 −1 −1 −j −j +1 +j +j−1 −j +j −1 +1 −1 +j +1 +j −j +j +1 −j −j −1 −1 −1 −j −j −1 −j −j +1 +j−j +1 −1 +1 −j −1 +j −j +j +1 −j −j −1 −1 −1 −j −j −1 −j −j +1 +j −j +1−1 +1 −j −1 −j +j −j −1 +j +j +1 +1 +1 +j +j +j −1 −1 −j +1 −1 −j +j −j−1 +j +1 −1 +1 −j −1 −1 +j +j +j −1 −1 −j +1 +1 +j −1 +1 +j −j +j +1 −j+1 −1 +1 −j −1 −1 +j +j +j −1 −1 The Sequence Seq³ _(right, 176)(k), tobe transmitted from left to right, up to down −1 −j −j +1 +j −j +1 −1 +1−j −1 +1 −1 +1 −j −1 −1 +j +j +j −1 −1 −j +1 +1 +j −1 +1 +j −j +j +1 −j−j +j −j −1 +j +j +1 +1 +1 +j +j −1 −j −j +1 +j −j +1 −1 +1 −j −1 +1 −1+1 −j −1 −1 +j +j +j −1 −1 +j −1 −1 −j +1 −1 −j +j −j −1 +j +j −j +j +1−j −j −1 −1 −1 −j −j −j +1 +1 +j −1 +1 +j −j +j +1 −j +j −j +j +1 −j −j−1 −1 −1 −j −j +1 +j +j −1 −j +j −1 +1 −1 +j +1 +1 −1 +1 −j −1 −1 +j +j+j −1 −1 +j −1 −1 −j +1 −1 −j +j −j −1 +j −j +j −j −1 +j +j +1 +1 +1 +j+j +1 +j +j −1 −j +j −1 +1 −1 +j +1 +1 −1 +1 −j −1 −1 +j +j +j −1 −1 TheSequence Seq⁴ _(right, 176)(k), to be transmitted from left to right, upto down −j +1 +1 +j −1 +1 +j −j +j +1 −j −j +j −j −1 +j +j +1 +1 +1 +j+j −j +1 +1 +j −1 +1 +j −j +j +1 −j +j −j +j +1 −j −j −1 −1 −1 −j −j +j−1 −1 −j +1 −1 −j +j −j −1 +j +j −j +j +1 −j −j −1 −1 −1 −j −j −j +1 +1+j −1 +1 +j −j +j +1 −j +j −j +j +1 −j −j −1 −1 −1 −j −j +1 +j +j −1 −j+j −1 +1 −1 +j +1 +1 −1 +1 −j −1 −1 +j +j +j −1 −1 +1 +j +j −1 −j +j −1+1 −1 +j +1 −1 +1 −1 +j +1 +1 −j −j −j +1 +1 +1 +j +j −1 −j +j −1 +1 −1+j +1 +1 −1 +1 −j −1 −1 +j +j +j −1 −1 −1 −j −j +1 +j −j +1 −1 +1 −j −1+1 −1 +1 −j −1 −1 +j +j +j −1 −1 The Sequence Seq⁵ _(right, 176)(k), tobe transmitted from left to right, up to down −1 −j −j +1 +j −j +1 −1 +1−j −1 +1 −1 +1 −j −1 −1 +j +j +j −1 −1 +j −1 −1 −j +1 −1 −j +j −j −1 +j+j −j +j +1 −j −j −1 −1 −1 −j −j +1 +j +j −1 −j +j −1 +1 −1 +j +1 −1 +1−1 +j +1 +1 −j −j −j +1 +1 +j −1 −1 −j +1 −1 −j +j −j −1 +j +j −j +j +1−j −j −1 −1 −1 −j −j −j +1 +1 +j −1 +1 +j −j +j +1 −j +j −j +j +1 −j −j−1 −1 −1 −j −j −1 −j −j +1 +j −j +1 −1 +1 −j −1 −1 +1 −1 +j +1 +1 −j −j−j +1 +1 −j +1 +1 +j −1 +1 +j −j +j +1 −j +j −j +j +1 −j −j −1 −1 −1 −j−j +1 +j +j −1 −j +j −1 +1 −1 +j +1 +1 −1 +1 −j −1 −1 +j +j +j −1 −1 TheSequence Seq⁶ _(right, 176)(k), to be transmitted from left to right, upto down −1 −j −j +1 +j −j +1 −1 +1 −j −1 −1 +1 −1 +j +1 +1 −j −j −j +1+1 +j −1 −1 −j +1 −1 −j +j −j −1 +j −j +j −j −1 +j +j +1 +1 +1 +j +j −1−j −j +1 +j −j +1 −1 +1 −j −1 −1 +1 −1 +j +1 +1 −j −j −j +1 +1 −j +1 +1+j −1 +1 +j −j +j +1 −j +j −j +j +1 −j −j −1 −1 −1 −j −j −j +1 +1 +j −1+1 +j −j +j +1 −j −j +j −j −1 +j +j +1 +1 +1 +j +j −1 −j −j +1 +j −j +1−1 +1 −j −1 +1 −1 +1 −j −1 −1 +j +j +j −1 −1 +j −1 −1 −j +1 −1 −j +j −j−1 +j +j −j +j +1 −j −j −1 −1 −1 −j −j −1 −j −j +1 +j −j +1 −1 +1 −j −1+1 −1 +1 −j −1 −1 +j +j +j −1 −1 The Sequence Seq⁷ _(right, 176)(k), tobe transmitted from left to right, up to down −1 −j −j +1 +j −j +1 −1 +1−j −1 −j +j −j −1 +j +j +1 +1 +1 +j +j −j +1 +1 +j −1 +1 +j −j +j +1 −j−1 +1 −1 +j +1 +1 −j −j −j +1 +1 −j +1 +1 +j −1 +1 +j −j +j +1 −j +1 −1+1 −j −1 −1 +j +j +j −1 −1 −1 −j −j +1 +j −j +1 −1 +1 −j −1 +j −j +j +1−j −j −1 −1 −1 −j −j −j +1 +1 +j −1 +1 +j −j +j +1 −j +1 −1 +1 −j −1 −1+j +j +j −1 −1 +1 +j +j −1 −j +j −1 +1 −1 +j +1 −j +j −j −1 +j +j +1 +1+1 +j +j −1 −j −j +1 +j −j +1 −1 +1 −j −1 −j +j −j −1 +j +j +1 +1 +1 +j+j +j −1 −1 −j +1 −1 −j +j −j −1 +j +1 −1 +1 −j −1 −1 +j +j +j −1 −1 TheSequence Seq⁸ _(right, 176)(k), to be transmitted from left to right, upto down +1 +j +j −1 −j +j −1 +1 −1 +j +1 −1 +1 −1 +j +1 +1 −j −j −j +1+1 +1 +j +j −1 −j +j −1 +1 −1 +j +1 +1 −1 +1 −j −1 −1 +j +j +j −1 −1 −j+1 +1 +j −1 +1 +j −j +j +1 −j +j −j +j +1 −j −j −1 −1 −1 −j −j +j −1 −1−j +1 −1 −j +j −j −1 +j +j −j +j +1 −j −j −1 −1 −1 −j −j +j −1 −1 −j +1−1 −j +j −j −1 +j −j +j −j −1 +j +j +1 +1 +1 +j +j +j −1 −1 −j +1 −1 −j+j −j −1 +j +j −j +j +1 −j −j −1 −1 −1 −j −j −1 −j −j +1 +j −j +1 −1 +1−j −1 +1 −1 +1 −j −1 −1 +j +j +j −1 −1 +1 +j +j −1 −j +j −1 +1 −1 +j +1+1 −1 +1 −j −1 −1 +j +j +j −1 −1

Millimeter wave (mmWave) precoding may be utilized in next generationwireless networks (e.g., WLAN) and cellular systems. Precoding at mmWavefrequencies may be digital such that, for example, an appropriatespatial mapping matrix may be used, analog such as, for example, bysetting appropriate Analog Weight Vectors, AWVs, for the DMG antennas,or a hybrid of digital and analog such as, for example, by setting acombination of AWVs and spatial mapping matrices.

Digital precoding may be precise, may be combined with equalization andmay enable single user (SU), multi-user (MU), and multi-cell precoding.Digital precoding may be used in sub 6 GHz, for example, in IEEE 802.11nand beyond and in 3GPP LTE Release 8 and beyond. However, in mmWavefrequencies, the presence of a limited number of RF chains compared withantenna elements and the sparse nature of the channel may addcomplexities when using digital beamforming.

Analog beamforming may overcome the limited number of RF chains issue byusing analog phase shifters on each antenna element. It may be used inIEEE 802.11ad during a Sector Level Sweep procedure during which thebest sector is identified, a Beam Refinement procedure during which thesector to an antenna beam is refined, and a beam tracking procedureduring which the sub-beams are adjusted over time to take into accountany change in the channel procedures. Analog beamforming may also beused in IEEE 802.15.3 where a binary search beam sounding algorithmusing a layered multi-resolution beamforming codebook is used. Analogbeamforming may be typically limited to single stream transmission.

In hybrid beamforming, the precoder may be divided between analog anddigital domains. Each domain may include precoding and combiningmatrices with different structural constraints such as, for example, aconstant modulus constraint for combining matrices in the analog domain.Such an implementation may result in a compromise between hardwarecomplexity and system performance. Hybrid beamforming may allow a systemto achieve digital precoding performance due to the sparse nature of thechannel and support for multi-user/multi-stream multiplexing. The numberof available RF chains may limit hybrid beamforming. However, thislimitation may not be a factor as mmWave channels are sparse in theangular domain.

According to implementations disclosed herein, hybrid-precodingprocedures for ODFM may be addressed. In 802.11ay for the OFDM basedPPDU, the packet structure may be different from that of a SingleCarrier (SC) PPDU. The use of OFDM may allow for implementation offrequency domain precoding and equalization. Accordingly, frequencydomain channel estimation and precoding information are needed,respectively. For channel estimation, a design for the EDMG CEFstructure for channel estimation and modification to the TRN fields maybe provided. For precoding in SU/MU-MIMO transmission, a modification tothe BRP procedure and a design for the associated packet structures maybe provided. An update to the hybrid precoding procedure, as comparedwith SC PPDUs, may also be provided.

According to the procedure, an initiator and responder may train the Txand Rx sectors and antennas using a MIMO Beamforming Setup/soundingprocedure. This procedure may identify the analog beams used for theMIMO transmission and may be specific for SU or MU MIMO. During the BFsounding subphase an EDMG BRP-Rx/Tx packet may be used for SU/MU-MIMO.The EDMG BRP-Rx/Tx packet may use waveform specific TRN fields. Theinitiator and responder may identify if the transmitted packet is an SCPPDU or an OFDM PPDU. For SC PPDUs, TRN-fields may be used as definedherein in relation to Table 1. For OFDM PPDUs TRN-fields may be used asfurther defined herein.

According to the procedure for hybrid precoding for OFDM based mmWaveMIMO, the link decision maker, such as the transmitter, may thentransmit a MIMO-setup frame/grant frame to indicate the desired analogbeams to be used. The link decision maker may be defined as the node inthe transmission that makes decisions regarding the antennaconfiguration to be used, estimates the precoder, determines a need forfeedback, and/or determines the type of feedback.

According to an implementation, the MIMO-setup frame/grant frame may beused to set up the parameters/capabilities of the STAs in the SU/MU-MIMOhybrid beamforming transmission. Alternatively or in addition, theparameters for the SU/MU-MIMO hybrid beamforming transmission may be setin a capabilities subframe. The capabilities may include an ability toperform hybrid beamforming, precoder Estimation/Feedback, waveformpreference for hybrid precoding, and/or precoder Parameters. Capabilityinformation may be exchanged during an association procedure may betransmitted in the beacon. For example, capability information may befound in one or more of the following frames: (1) Association RequestFrame format (2) Association Response Frame Format (3) ReassociationRequest frame format (4) Reassociation Response frame format (5) ProbeRequest frame format and/or (6) Probe Response frame format (7) DMGbeacon.

The ability for precoder estimation and/or feedback may indicate if theSTA can estimate a baseband precoder, can facilitate feedback for thebaseband channel only, can both estimate and facilitate feedback for thebaseband precoder and the baseband channel, or none of these featuressuch that, if none, then the hybrid beamforming may require channelestimation of the reverse channel only. The waveform preference forhybrid precoding may be SC, ODFM, or both and the packet mode maydetermine the EDMG-CEF of the appropriate type and dimension. Precoderparameters may be time domain channel feedback such as, for example, thenumber of taps of the time domain channel to be fed back and/orfrequency domain channel feedback such as, for example, the number ofsub-carriers per feedback).

A setup/grant frame may be transmitted in SU mode to one or multipleSTAs. The grant may be sent in SU mode by successive single sectors toeach STA in the transmission or based on a desired configuration.Interframe spacing (IFS) between successive grant frames may be set toshort interface space (SIFS) or any appropriate interframe spacing suchas, for example, BRP interframe space (BRPIFS), Medium BeamformingInter-frame Spacing (MBIFS), Short Beamforming Inter-frame Spacing(SBIFS), etc.

The grant may be transmitted using the control PHY or may be transmittedusing the desired PHY, for example SC verses OFDM. If the control PHY isused, the grant frame may explicitly indicate the desired PHY mode (SCor OFDM PPDU). If the grant frame is transmitted using an SC or OFDMPPDU, this may implicitly signal the type of measurement and feedback tobe used.

The grant may signal the parameters of a current measurement procedure.For example, the signal may indicate if feedback is needed. A forwardlink measurement, in the case where there is no reciprocity, may needsome form of feedback to the transmitter whereas a reverse linkmeasurement, in the case where there is reciprocity, may not. Iffeedback is needed such that the measurement is made in the forwardlink, then the type of feedback needed may be indicated. For example,the indication may include a precoder feedback or baseband channel. Thebaseband channel estimate feedback may be a time domain channel estimateor a frequency domain channel estimate. The type of channel estimate maydepend on the capability of the receiver or on the decision maker, asdescribed herein, in the measurement setup. Additionally, samplingrate/granularity of feedback may be indicated and may depend on thecapability of the receiver or on the decision maker in the measurementsetup or on the frequency selectivity of the channel. Signaling thegranularity of the feedback may be explicit or implicit. As an implicitexample, the OFDM EDMG-CEF per-symbol duration may be reduced to 1/n, bysampling every n tones in OFDM EDMG-CEF, and then truncating the firstperiod per symbol in time domain. The symbol duration used may then besignaled in the EDMG Header-A or other field in the preamble. Thegranularity of the feedback may be set to the same sampling rate usedfor the EDMG-CEF.

Further, when a MIMO-step frame/grant frame is received, the STA mayperform multi-sector clear channel assessment, as discussed herein. TheSTA may perform a preamble detection or energy detection on one or moreof the sectors, such as beam-pair and/or antenna, to establish that thesector(s) are free to transmit/receive information without impactingtheir own, or other, transmissions. The feedback information may includethe status of each sector, such as beam-pair and/or antenna, to allowfor rank adaptation in SU-MIMO transmission or rank and STA adaptationin MU-MIMO. The feedback frame may be sent on a single SU sector, MUsectors, or both SU and MU sectors. The STA may not send feedback for asector/channel clear frame and an absence of hybrid precoding feedbackmay indicate that that channel/sector was not clear.

Further, a transmitter may then acquire the hybrid beamforminginformation. The hybrid beamforming information may be the basebandchannel for a specific sector/beam/beam-pair/antenna configuration in aSU-MIMO transmission between the transmitter and responder or in anMU-MIMO transmission between a transmitter and a specific set of STAs.When the information is acquired by the transmitter and then used todesign the baseband precoder, then the acquisition may be by explicitfeedback of the channel or a compressed version of the channel and/or byacquisition of the reverse channel from the receiver to the transmitterin the case of reciprocity.

Alternatively or in addition, the hybrid beamforming information may bethe baseband precoder for a specific sector/beam/beam-pair/antennaconfiguration in a SU-MIMO transmission between the transmitter andresponder or in an MU-MIMO transmission between a transmitter and aspecific set of STAs. When the information is derived from measurementof the baseband channel, then the acquisition may be explicit feedbackof the derived precoder or a compressed version of the derived precoder.

The hybrid precoding information may differ for SC verses OFDM PPDUs. Ina scenario where there is an SC PPDU, information for a single precodermay be acquired such as the time domain channel estimate of the channel.The receiver may design the precoder.

In a scenario where there is an OFDM PPDU, information for multipleprecoders may be acquired to enable accurate precoders across thefrequency domain. In this scenario the information may be the timedomain channel estimate of the channel or the frequency domain channelestimate, such as the effective baseband MIMO channel, for eachsub-carrier or a group of subcarriers. The receiver, such as theeffective baseband MIMO channel, may design the precoder for eachsub-carrier or group of sub-carriers.

For either scenario, one or more significant taps of the time domainchannel may be acquired (fed back or acquired by reciprocity) and as thenumber of taps increases, the accuracy of the design precoder mayimprove.

Further, for both SC and OFDM PPDU, it may be necessary for the basebandchannel to be measured. According to an implementation, the transmittermay measure the baseband channel as part of a beam tracking procedure.The tracking request may be sent as part of the configuration frame(using the DMG and EDMG Header-A fields) or may be sent as anindependent transmission.

The channel measurement for tracking may be based in several examples.In one example, SC or OFDM TRN fields may be appended to the end of theframe with multiple TRN fields using different adaptive weight vectors(AWVs) to identify optimal beams/sectors/antennas and the correspondinghybrid beamforming feedback. This method may allow the tracking of boththe analog beams and the digital baseband channel. The EDMG-CEF may beset appropriately for the waveform (SC or OFDM).

In another example, SC or OFDM TRN fields may be appended to the end ofthe frame with multiple TRN fields using the same AWV used for theSU-MIMO or MU-MIMO transmission to identify the hybrid beamformingfeedback for the current transmission. This method may allow reducingthe appended TRN-units in the case that the analog beams are fixed. TheEDMG-CEF may be set appropriately for the waveform (SC or OFDM).

In another example, the appended TRN-units may be eliminated from theBRP tracking frame and the SC EDMG-CEF or OFDM EDMG-CEF may be used inthe transmitted packet to measure the effective channel. This method mayfurther reduce the overhead. Note that the EDMG-CEF may be setappropriately for the waveform (SC or OFDM) and may be of theappropriate dimension such as to enable measurement of the desiredtransmit antenna/beam/beam-pair/sector configuration.

The beam tracking procedure may measure the forward channel from thetransmitter to the receiver by using EDMG initiator transmit beamtracking; this may then require feedback of the hybrid precoderinformation to the initiator (transmitter). The beam tracking proceduremay measure the reverse channel from the receiver to the transmitter.The reverse channel may be estimated by having the EDMG respondertransmit beam tracking or having the EDMG initiator receive beamtracking; this assumes channel reciprocity.

Alternatively or in addition, the transmitter may measure the basebandchannel as part of a BRP procedure. The BRP request may use theappropriate TRN fields for the transmitted EDMG waveform. The channelmeasurement for the BRP procedure may be based on appending SC or OFDMTRN fields to the end of the frame with multiple TRN fields usingdifferent AWVs to identify the best beams/sectors/antennas and thecorresponding hybrid beamforming feedback. This technique may allow theflexibility of allowing the tracking of both the analog beams and thedigital baseband channel. Note that the EDMG-CEF may be setappropriately for the waveform (SC or OFDM). Additionally, in the BRPmethod, the receiver may respond with an ACK and feedback for theinformation at a more appropriate time.

According to an implementation, the transmitter may acquire the hybridprecoding information as part of a null data packet exchange with thereceiver. At a SIFS duration after the configuration frame, thetransmitter may send a dedicated EDMG frame that contains no data (anEDMG Null Data Packet Frame) to request for hybrid precodinginformation. The EDMG packet may contain data (and EDMG basebandmeasurement packet) but the dimensions of the EDMG-CEF must besufficient to measure the desired channel.

If feedback is needed, the port control protocol (PCP)/AP and STAs mayswitch antenna configurations back to the SU for single streamtransmission for each STA. Alternatively, the feedback may bepiggybacked on any transmission to the transmitter. The interframespacing between measurement frame null data packet (NDP) and thefeedback frame from the first STA may range between SIFS and BRPIFS.Additionally, the order of feedback may be different from the order ofthe grant frame transmission and the specific order of feedback may besignaled.

The STAs may send feedback hybrid precoding information, if needed. Thismay be the effective baseband channel or may be an estimated precoder.The channel or estimated precoder may be fed back in full detail or itmay be fed back in compressed form.

Further, the transmitter may use hybrid precoding information withanalog beams to construct the hybrid beamform/precoder and transmit datato the receiving STA(s).

FIG. 12 shows an example procedure according to an implementationdisclosed herein.

As shown in FIG. 12, at 1210 one or more STAs may be setup, includingtheir SU Antenna Configuration. As noted, STA2/3 may send a single grantframe if it is within the same sector as the other STAs. Additionally,STAs may be setup with an applicable interval, such as a SIFS. At 1220,the SU antennas may be configured with SIFS intervals, as shown, if CCAfeedback is needed. 1230 shows an MU antenna configuration that ispreceded and followed by an applicable interval such as a SIFS or BRPIFSinterval. The MU antenna configuration fields include a Pad field aswell as an EDMG NDP/Tracking Field. At 1240, the SU antennas may befurther configured with SIFS intervals, as shown, if feedback is needed.

According to an implementation, the BRP frame structure may be used forhybrid beamforming sounding in an OFDM system. A BRP procedure may be arequest response based procedure and the OFDM feedback request/responsemay be implemented using BRP frame exchanges. A BRP frame may need to bemodified to request and carry feedback information for an OFDM system.An example of a BRP frame is shown table 2 below. Fields that may beprovided and/or updated may be a BRP Request field and/or EDMG BRPrequest element, a DMG Beam Refinement element, and Channel MeasurementFeedback elements or EDMG Channel Measurement Feedback elements.

TABLE 2 BRP Frame Format Order Information 1 Category 2 Unprotected DMGAction 3 Dialog Token 4 BRP Request field 5 DMG Beam Refinement element6 Zero or more Channel Measurement Feedback elements 7 EDMG PartialSector Sweep element 8 EDMG BRP Request element (optional) 9 Zero ormore EDMG Channel Measurement Feedback elements

BRP feedback request and/or configuration signaling may be applied suchthat a BRP frame may be transmitted from STA1 to STA2 where BRP feedbackrequest related signaling and/or BRP feedback configuration signalingmay be contained. The BRP feedback request signaling may be set by STA1to indicate what kind of feedback may be requested from STA2. The BRPfeedback configuration signaling may be set by STA1 to indicate theformat and length of the DMG/EDMG channel measurement fields presentedin the current BRP frame.

OFDM baseband tracking requests, OFDM baseband feedback types, andfeedback request details may be specified as BRP feedback requests whenOFDM time/frequency domain channel state information (CSI) is preferred.

For OFDM baseband tracking request the choice of OFDM or SC digitalbaseband tracking may be implicit. For example, if the PPDU that carriesthe BRP frame is an OFDM PPDU, then the digital basebandtracking/sounding field may indicate that it is for OFDM digitalbaseband tracking/sounding and OFDM feedback may be requested. If thePPDU that carries the BRP frame is an SC PPDU, then the digital basebandtracking/training field may indicate that it is for SC digital basebandtracking/sounding and SC feedback may be requested. Alternatively, OFDMbaseband tracking request may be replaced by digital basebandtracking/training.

OFDM baseband feedback type may be time domain feedback or frequencydomain feedback. Alternatively, an OFDM baseband feedback type may notbe explicitly signaled, and instead it may be implicitly signaled. Forexample, if an OFDM feedback may be requested, then frequency domainfeedback may be requested. If a SC feedback may be requested, then timedomain feedback may be requested.

The feedback request detail for frequency domain OFDM feedback requestsmay include Ng, which indicates that one feedback for every N adjacentsub-carrier may be request ted. For example, N may be [4, 8, 16, 24, 32,64]. The number of bits for each feedback coefficient may indicate therequested feedback coefficients resolution. For example, if the givenrotation may be used to compress a V matrix, two angle sets may beprovided as feedback. Angles may be quantized using the number of bitsindicated for each angle set. Digital MIMO channel dimensions may be thenumber of Tx streams/chains (Ntx) to be trained, and the number of Rxstreams/chains (Nrx) to be trained. Alternatively, Nrx or Ntx may not berequested, and may be determined by the STA, which may perform themeasurement, e.g., STA2.

OFDM baseband feedback type and feedback detail configurations may bespecified as BRP feedback configurations in the case that OFDMtime/frequency domain channel state information (CSI) may be preferred.

OFDM baseband feedback type may indicate the feedback type used in thechannel measurement element or EDMG channel measurement element such astime domain feedback or frequency domain feedback. Alternatively, OFDMbaseband feedback type may not be explicitly signaled, and instead maybe implicitly signaled. For example, if an OFDM feedback is requested,then frequency domain feedback is requested. If a SC feedback isrequested, then time domain feedback is requested. The channelmeasurement or EDMG channel measurement element may be replaced by theEDMG baseband precoder element that feeds back the elements of one ormore time domain or frequency domain precoders derived by the receiverfrom the estimated channel. The precoder may be designed based on thebaseband channel only, or it may be jointly designed with the analogbeams based on an estimate of the millimeter wave channel.

The feedback detail configurations for frequency domain OFDM feedbackrequests may include Ng, which indicates that one feedback for every Nadjacent sub-carrier may be requested. For example, N may be [4, 8, 16,24, 32, 64]. The number of bits for each feedback coefficient mayindicate the requested feedback coefficients resolution. For example, ifthe given rotation may be used to compress V matrix, two angle sets maybe provided as feedback. Angles may be quantized using the number ofbits indicated for each angle set. Digital MIMO channel dimensions maybe the number of Tx streams/chains (Ntx) to be trained, and the numberof Rx streams/chains (Nrx) to be trained.

Some or all of the signaling discussed herein may be indicated in theBRP Request field, EDMG BRP request element and/or the DMG beamrefinement element. In one example, OFDM baseband tracking request or abaseband tracking request field may be carried using reserved bit in BRPRequest field and/or EDMG BRP request element. In another example, OFDMbaseband feedback type field may be carried using reserved bit in BRPRequest field, and/or EDMG BRP request element.

In another example, OFDM feedback request details and/or feedback detailconfigurations may be carried in DMG Beam Refinement element. Forexample, DMG Beam Refinement element may be modified from FIG. 13 toFIG. 14.

As shown in FIG. 13, an existing DMG beam refinement element may includean Element ID 1301 (8 bits), a length 1302 (8 bits), an initiator 1303(1 bit), a TX-train-response 1304 (1 bit), a RX-train-response 1305 (1bit), a TX-TRN-OK 1306 (1 bit), a TXSS-FBCK-REQ 1307 (1 bit), a BS-FBCK1308 (6 bits), a BS-FBCK Antenna ID 1309 (2 bits), a Digital FBCK-REQ1310 (5 bits), a FBCK-TYPE 1311 (18 bits), a MID Extension 1312 (1 bit),a Capability Request 1314 (1 bit), a Reserved field 1315 (2 bits), aBS-FBCK MSB 1316 (4 bits), a BS-FBCK Antenna ID MSB 1317 (1 bit), aNumber of Measurements MSB 1318 (4 bits), an EDMG Extension Flag 1319 (1bit), a EDMG Channel Measurement Present 1320 (1 bit), a Short SSWPacket Used 1321 (1 bit), a BRP-TXSS OK 1322 (1 bit), a BRP-TXSSresponse 1323 (1 bit) and a reserved field 1324 (2 bits).

As shown in FIG. 14, a modified DMG beam refinement element may includean Element ID 1401 (8 bits), a length 1402 (8 bits), an initiator 1403(1 bit), a TX-train-response 1404 (1 bit), a RX-train-response 1405 (1bit), a TX-TRN-OK 1406 (1 bit), a TXSS-FBCK-REQ 1407 (1 bit), a BS-FBCK1408 (6 bits), a BS-FBCK Antenna ID 1409 (2 bits), a combined DigitalFBCK-REQ/Type 1411 (23 bits), a MID Extension 1412 (1 bit), a CapabilityRequest 1414 (1 bit), a Reserved field 1415 (2 bits), a BS-FBCK MSB 1416(4 bits), a BS-FBCK Antenna ID MSB 1417 (1 bit), a Number ofMeasurements MSB 1418 (4 bits), an EDMG Extension Flag 1419 (1 bit), aEDMG Channel Measurement Present 1420 (1 bit), a Short SSW Packet Used1421 (1 bit), a BRP-TXSS OK 1422 (1 bit), a BRP-TXSS response 1423 (1bit), a Digital BF 1424 (1 bit) and a reserved field 1425 (1 bit).

As shown, one reserved bit 1425 from FIG. 14 may be used to indicatewhether Digital BF related feedback Request/Type may be included. Ifthis bit is set, then feedback FBCK-REQ 1310 and FBCK-TYPE 1311 fieldsof FIG. 13 may be overwritten as FBCK-REQ/TYPE field 1411 of FIG. 14.

The FBCK-REQ/TYPE field 1411 may be defined based on one or moreimplementations. In accordance with a first implementation, M bits maybe used as OFDM/Digital FBCK-REQ field 1310 of FIG. 13 and N bits may beused as OFDM/Digital FBCK-TYPE field 1411 of FIG. 14. For example,M+N<=23. The M bit OFDM/Digital FBCK-REQ field 1310 may carry OFDMfeedback request detail information. The N bit OFDM/Digital FBCK-TYPEfield 1411 may carry OFDM feedback configuration information. Accordingto this implementation, the BRP frame may be used to carry feedbackconfiguration information that indicates the length and format of thechannel measurement element carried in the same BRP frame. At the sametime, it may carry request information for the later BRP sounding. Inaccordance with another implementation, one bit in the OFDM/DigitalFBCK-REQ/TYPE field 1411 may indicate the field that may be used tocarry either OFDM/Digital FBCK-REQ field 1310 or OFDM/Digital FBCK-TYPEfield 1311. OFDM/Digital FBCK-REQ field 1310 or OFDM/Digital FBCK-TYPEfield 1311 may be limited by a total of 23 bits. The OFDM/DigitalFBCK-REQ field may carry OFDM feedback request details information ifthe first bit is set. If the first bit is not set, OFDM feedbackconfiguration information may be carried. According to thisimplementation, the BRP frame may carry either feedback requestinginformation or the feedback configure information, but may not carryboth. A benefit form this configuration may be that more detailedinformation is carried and more bits may be used as reserved bits.Alternatively, according to another implementation, more bits may beoverwritten and reused to carry OFDM/Digital tracking/soundinginformation. For example, Number of Measurements most significant bit,MSB field, EDMG Extension flag field, etc.

According to an implementation, clear channel assessment (CCA) during SUand MU MIMO BF training may be addressed. CCA may be important in 802.11as it may prevent non-transmitting STAs from interrupting on-goingtransmissions. Methods to implement CCA during the use of multipledirectional antennas are needed especially during sounding. TRN refersto the TRN field appended at the end of a PPDU, any other portion of aPPDU, or an entire PPDU or series of PPDUs that is or are used for BFtraining or beam refinement/tracking.

For SU/MU MIMO BF training or beam tracking, there may be limitationsthat certain AWVs in the TRN may interfere with other ongoing receptionsof non-intended STAs. Additionally, the intended STA such as theresponder's reception of certain AWV may be interfered by thetransmissions of other STAs' ongoing transmissions. This may negativelyimpact either the result of the BF training or the ongoing communicationof other STAs. An STA, such as an initiator, may perform one or moreCCAs based on the antennas/AWV/RF chains that are used to transmit orreceive TRN. The CCA may be based on any of the disclosed criteriaperformed on a channel that occupies the same or a subset of BW of TRNto be transmitted/received.

The CCA may be based on NAV setting per antenna/AWV/RF chain where itmay be assumed that there are several NAV timers each of which keeptrack of the NAV of an antenna/AWV/RF chain combination. The Rx patternof the antenna/AWV/RF chain combination used for maintaining a NAV timermay be a super set of the antenna pattern of the antenna/AWV/RF chainused in transmitting/receiving TRN. Also, the NAV timer corresponding toa Tx antenna/AWV/RF chain may be set based on the duration field of adecoded MAC protocol data unit (MPDU) which is received in an antennapattern that covers the Tx/Rx pattern of the antenna/AWV/RF chain thatis used for transmitting/receiving TRN.

Alternatively, the CCA may be based on energy detection perantenna/AWV/RF chain where the detection is performed in an antennapattern that covers the pattern of the antenna/AWV that is used fortransmitting/receiving TRN. The detection may be based on the receivedenergy in an interframe space, xlFS, duration. If TRN comprisesdifferent antenna/AWV combinations of the same RF chain that cannot beactivated at the same time, then the energy detection may involve areceive sector sweep (RXSS) of the RF chain that changes its antennaconfiguration every xlFS duration for the energy detection.

The initiator may not transmit TRN on the antenna/AWV/RF chain where theCCA is indicated as busy. An indication may be included in a frame/PPDUto the responder indicating that the BF sounding only includes a subsetof transmit/receive settings that the initiator intends to test. Suchindication may be used by responder not to commit to an Rx/Tx patternthat is only optimized for the TRN received/transmitted in thissounding. The indication may also be used by the responder not toprovide complete feedback until all transmit settings of the initiatorhave been tested. The responder may also use the indication such thatthe responder does not expect a complete feedback until all receivedsettings of the initiator have been tested.

One or more NAV setting frames may be sent to protect the TRN to betransmitted or to be received by the initiator. A duplicated NAV settingframe may be sent in different antennas/AWVs/RF chains that are used totransmit or receive TRN. The duplicated NAV setting frame may not besent on antenna/AWV/RF chain that has CCA indicated as busy Theduplicated frame may be sent with a cyclic shift diversity (CSD) fromdifferent antennas/AWVs/RF chains.

The NAV setting frame may be transmitted in a duplicated format thatcovers the entire BW used by TRN. If TRN comprises different antenna/AWVcombinations of the same RF chain that cannot be activated at the sametime, then consecutive NAV setting frames may be sent, with the RF chainswitching antenna configuration for each frame, and/or with each frameseparated with an interframe space duration ylFS. The NAV setting framesent by the initiator may be a MIMO BF setup frame, request to send(RTS) or clear to send (CTS)-to-self frame.

The NAV setting frame may solicit a NAV setting frame from a responder.The responding NAV setting frame may be used to protect the TRN to betransmitted or to be received by the responder; this may be enabled onlywhen the responder has already enabled an Rx setting that is used forCCA at the Rx side before the transmission of the NAV setting frame fromthe initiator, and the BF training does not test a different Rx settingat the responder. In case multiple consecutive NAV setting frames aresent by the initiator, an implicit or explicit time offset may bespecified in the PPDU for the timing of the NAV setting frame from theresponder. In case the NAV setting frame is addressed to more than oneSTA, an implicit or explicit time offset may be specified in the PPDUfor the timing of the NAV setting frame from the responder. The NAVsetting frame from the responder may be MIMO BF setup frame or DMG CTSframe.

The responder may not respond to the NAV setting frame from theinitiator, which solicits a responding NAV setting frame from theresponder, if the one or more or all of the antenna/AWV/RF chain(s) atthe responder indicate(s) that the CCA is busy. The criteria ofdetermining whether the CCA is busy may be the same as discussed hereinregarding the initiator, such that it is based on the TRN to betransmitted or received by the responder.

If the responder determines to respond with the solicited NAV settingframe, then the criteria of sending a duplicated frame in theantenna/AWV/RF chain, and channel, may be the same as described for theinitiator.

The responder may not transmit TRN on the antenna/AWV/RF chain that hasthe CCA indicated as busy. An indication may be included in a frame/PPDUto the initiator indicating that the BF training only includes a subsetof transmit/receive settings that the responder intends to test. Suchindication may be used by the initiator not to commit to an Rx/Txpattern that is only optimized for the TRN received/transmitted in thissounding. The indication may also be used by the initiator to notprovide complete feedback until all transmit settings of the responderhave been tested. The indication may also be used by the initiator tonot expect a complete feedback until all receive settings of theresponder have been tested.

After an initiator or responder transmits TRN, the initiator orresponder may perform feedback. In the feedback, an indication may beused to indicate that when sounding is performed for a particular Tx/Rxsetting, for example a TRN index/spatial stream, the receiver reportsthe CCA to be busy. The reported SNR/RSSI/channel measurement may beconsidered inaccurate for this Rx/Tx setting based on this busyindication. This CCA busy report may be based on the total receivedenergy and the quality of expected sounding signals from thetransmitter.

According to an implementation, the TRN structure and design for OFDMmay address the TRN structure for digital/analog/hybrid beam sounding,the flexibility of TRN structure, and the TRN structure for hardwarenon-linearities. In order to extend the coverage during the TRN fieldtransmission, the TRN field may have low peak average power ratio(PAPR). However, the available sequences, such as those used for EDMGCEF for OFDM, have approximately 3-3.5 dB PAPR, which may limit thecoverage range. Further, 802.11ay SC PHY may introduce flexibility tothe size of the TRN fields. However, it may not be trivial to achieve asimilar flexibility to the TRN for SC as described herein, for examplethe disclosure relating to table 1, since number of samples at theoutput of the inverse discrete Fourier transform (IDFT) for OFDM isconstant. Also, the OFDM symbol may have a higher PAPR regardless of themodulation symbols in the payload. Hence, OFDM PHY may be sensitive tohardware non-linearities, especially for millimeter wave communications.

The PPDU related to TRN for OFDM may have a structure for digitalprecoding sounding and hybrid beamforming sounding. According to animplementation, for digital precoding sounding, the PPDU 1500 may notinclude data packets or TRN, as shown in FIG. 15. As shown, the PPDU1500 may include a L-STF (SC) 1501, a L-CEF (SC) 1502, a L-Header (SC)1503, an EDMG Header (SC) 1504, an EDMG STF (OFMD) 1505, and an EDMG CEF(OFMD) 1506. The header 1503/1504 may indicate the PPDU 1500 does notinclude data packets or TRN. The receiver may send feedback based on theestimated channel based on the EDMG CEF 1506 field for OFDM. Accordingto this implementation, analog beamforming may be fixed. Additionally oralternatively, as shown in FIG. 16, digital precoding sounding PPDUs maynot have data packet, the header may indicate this structure, and thereceiver may send feedback of the estimated channel based in the TRNfield. As shown, the PPDU 1600 may include a L-STF (SC) 1601, a L-CEF(SC) 1602, a L-Header (SC) 1603, an EDMG Header (SC) 1604, a EDMG STF(OFMD) 1605, an EDMG CEF (OFMD) 1606, and a TRN (OFDM) 1607.

According to an implementation for hybrid beamforming sounding, PPDU SCsounding may be used for OFDM based sounding for analog beamformingsounding. If the channel response is fed back to the initiator, thetransmit and receive filter(s) may be predefined or signaled so that theinitiator removes the impact of filters from the effective channel tolearn the actual mmWave multipath channel for OFDM transmission.

FIG. 17 shows a PPDU 1700 including a L-STF (SC) 1701, a L-CEF (SC)1702, a L-Header (SC) 1703, an EDMG Header (SC) 1704, a EDMG STF (OFMD)1705, an EDMG CEF (OFMD) 1706, a Payload (OFDM) 1707, a TRN (OFDM) 1708,and a TRN (SC) 1709. According to an implementation, as shown in FIG. 17for a hybrid beamforming sounding PPDU, the EDMG Header (SC) 1704 mayindicate the type of waveform for the TRN (SC) field 1709. For SC, thefeedback may only contain the quality information, such as the SNR/SINRor ID of best beams, corresponding to the beams that have been swept.For OFDM, the feedback may also be related to the channel frequency fora group of beams that have been swept. The content of information may bethe baseband precoding matrix, for example, derived based on singularvalue decomposition (SVD), the channel coefficients in time (on a groupof taps) or frequency (on a group of subcarriers), and/or the rankinformation for multibeam sounding.

According to an implementation, the TRN may have a structure such thatthe OFDM TRN field and SC TRN field may be configured with identicalparameters. For example, 802.11 ay defines P, N, M, K, which correspondto RX-TRN units per TX TRN unit field, and the number of TRN units inthe header. The same structure may be employed for OFDM while the TRNfield is an OFDM symbol, and not an SC symbol. According to animplementation, the TRN field may use exactly the same sequences definedfor 802.11ay EDMG CEF OFDM. This option is shown in the example diagramof FIG. 18. As shown, PPDU 1800 includes an L-STF (SC) 1801, a L-CEF(SC) 1802, a L-Header (SC) 1803, an EDMG Header (SC) 1804, a EDMG STF(OFMD) 1805, an EDMG CEF (OFMD) 1806, a Payload (OFDM) 1807, a TRN(OFDM) 1808, TRN Units including TRN Unit 1 1820 through TRN Unit K 1830where RX TRN-Units per TX TRN Unit Field: K and which include parametersP 1821, N 1822, and M 1823. As shown in FIG. 18, the TRN field 1808 usesexactly the same sequences defined for 802.11 ay EDMG CEF (OFDM) 1810.

According to an implementation, the TRN field may use computer generatedconstant amplitude sequences to reduce the PAPR. The computer generatesequences may be or include an element of M-PSK constellation. The timecyclic shift of the time-domain footprint of these sequences may beemployed for different streams. In the frequency domain, modulating thebase/original sequence may generate these shifts. For example, one mayconsider a sequence for left and right sequences where M=64 andphases=exp(1i*2*pi*[0:M−1]/M). Then, Sleft from Table 3 may be chosenfor a given channel bounding size Ncb and IFFT size. Then, Sright fromTable 3 may be chosen for a given channel bounding size Ncb and IFFTsize. The Total Sequence may result in: [phases(Sleft); 0; 0; 0;phase(Sright)]. Table 3 shows an example for 64 PSK sequences thatachieves low PAPR.

TABLE 3 PAPRN (N Nifft = is the IFFT (Nominal size used at IFFT size)Sleft Sright transmitter) Ncb = 1, 1 13 56 60 31 11 61 63 52 37 56 12 3346 PAPR512: Nifft = 25 54 49 6 50 47 8 50 46 4 27 37 37 1 1.1715 512 2544 21 31 58 39 63 40 50 39 14 58 14 14 40 28 9 17 51 17 54 13 38 62 58 418 46 12 6 6 49 3 57 27 31 31 34 55 17 35 34 33 22 63 51 39 63 16 15 346 54 45 51 39 44 31 53 16 26 53 3 45 44 45 30 63 17 36 5 62 22 31 13 4428 8 36 61 11 19 57 47 46 48 46 29 52 51 58 33 56 54 37 37 39 32 52 6310 64 2 45 56 15 11 47 16 25 34 58 25 21 54 54 56 4 52 19 3 49 11 18 1048 59 33 56 42 16 23 51 2 59 20 9 35 56 38 16 27 58 46 24 15 43 43 8 112 61 17 8 40 3 27 3 59 3 12 49 47 43 23 13 57 7 26 58 28 29 19 32 46 5416 44 37 1 56 45 48 11 16 36 30 8 39 12 46 14 11 7 33 53 45 57 36 62 525 16 17 14 18 62 61 8 64 51 3 38 40 58 42 9 41 20 30 58 13 4 63 31 40 2961 2 28 49 21 2 55 6 50 21 26 18 35 42 52 27 51 4 57 18 24 32 7 36 49 5463 30 35 24 61 13 25 5 32 16 36 23 61 15 31 40 53 48 36 10 8 14 13 1 4342 36 55 6 46 28 22 15 11 31 1 38 4 56 60 45 39 11 52 4 11 56 22 17 9 5321 2 57 47 11 16 13 10 44 12 13 12 18 18 56 7 5 32 63 26 Ncb = 1, 1 1931 57 27 53 3 58 61 45 23 28 5 53 PAPR512: Nifft = 47 6 59 21 36 60 3237 50 27 4 38 3 57 2.2562 1024 24 5 57 30 56 48 21 11 54 13 54 29 45 1PAPR1024: 52 54 11 10 26 13 9 55 23 1 8 46 12 49 2.3574 6 26 46 1 28 3012 51 53 18 1 18 51 56 PAPR1536: 27 55 15 55 39 41 25 9 28 10 46 36 2 582.5067 26 43 51 48 48 53 1 2 20 34 37 55 3 31 PAPR2048: 47 50 5 1 7 48 530 38 32 37 51 61 12 9 2.4063 19 26 25 14 53 41 2 22 44 34 14 28 35 56PAPR4096: 55 48 17 22 4 45 64 29 2 44 17 11 39 48 2.5121 56 50 12 58 1453 56 27 42 15 52 25 20 11 42 4 55 4 25 39 29 19 43 32 20 54 33 41 26 2144 18 7 59 7 35 39 26 8 41 59 13 28 46 15 16 23 53 62 28 58 32 15 38 3834 17 43 1 38 60 26 49 38 29 26 58 15 60 22 54 44 46 53 38 38 8 10 62 6263 29 57 61 54 3 36 45 27 10 55 44 24 21 47 55 38 12 14 64 6 19 54 39 106 33 57 55 57 2 19 60 52 18 52 17 15 6 62 51 4 50 40 39 36 6 54 60 24 3554 27 55 39 35 36 48 3 12 31 3 20 18 2 12 57 21 41 8 14 23 62 49 40 6234 45 14 50 10 41 30 11 63 41 27 24 62 56 44 11 13 28 39 18 19 17 57 5517 8 17 58 52 64 12 15 35 27 63 5 19 32 27 11 13 47 3 62 17 16 63 56 657 37 6 30 9 47 Ncb = 2, 1 25 64 23 8 45 46 57 49 13 5 6 31 7 PAPR1024:Nifft = 18 31 1 48 19 13 53 58 46 64 48 58 60 23 1.0710 1024 62 18 12 5126 60 37 30 25 3 39 57 33 52 26 24 22 11 55 63 19 22 61 16 61 63 21 5956 58 32 55 45 22 46 50 43 50 3 40 2 55 34 37 33 22 19 45 46 3 57 42 5338 43 37 47 50 28 60 9 52 45 6 49 16 62 24 12 61 52 15 33 18 41 2 14 1323 8 7 53 2 52 8 16 38 60 54 43 17 46 45 12 52 9 1 9 37 24 29 63 22 2648 49 21 9 27 55 46 61 14 2 51 17 35 41 17 19 55 21 36 30 22 2 16 50 2142 50 41 8 1 40 48 53 9 39 15 50 55 21 24 22 6 36 11 27 6 56 49 53 3 5143 26 58 19 5 7 48 51 1 45 49 12 61 47 41 1 14 21 15 23 49 49 6 24 49 3316 45 44 23 54 41 16 47 27 54 58 52 32 43 51 38 50 50 22 8 38 59 29 5856 32 42 64 34 64 57 55 59 17 43 50 1 16 1 13 11 39 20 50 62 54 11 35 2241 6 42 6 7 47 38 55 6 51 11 49 59 41 17 29 41 32 36 49 61 47 19 58 5317 58 55 45 19 13 37 60 56 15 7 45 21 3 22 12 7 16 35 33 31 16 27 35 6014 32 51 6 43 39 45 41 3 29 47 53 47 55 9 14 13 44 18 19 4 19 23 17 4245 60 26 10 36 7 15 47 51 7 53 59 4 40 9 42 46 45 63 15 20 33 37 59 5010 42 1 51 1 36 55 43 64 29 39 38 15 46 24 14 14 17 19 32 52 17 19 43 455 35 26 35 7 36 29 30 24 26 2 7 27 9 53 9 2 59 41 62 2 51 30 25 22 5739 27 45 46 25 10 62 48 2 35 23 60 38 43 53 40 17 28 37 58 10 41 4 6 5158 16 49 25 25 6 32 29 40 38 10 56 22 43 63 44 42 17 16 52 51 58 44 1362 36 21 49 50 53 17 25 27 31 53 18 30 64 55 16 21 25 2 23 4 4 3 32 1523 47 32 35 28 4 6 13 45 4 12 4 47 50 20 19 26 11 8 30 33 47 61 35 57 954 43 36 27 63 6 38 20 21 22 57 13 10 51 53 55 45 43 22 60 56 9 48 38 91 5 61 16 48 21 59 28 54 61 48 25 26 2 27 52 50 61 46 25 2 41 11 22 2952 35 52 12 5 28 5 27 44 22 9 32 61 5 36 9 54 42 62 49 36 29 27 1 53 118 10 47 38 25 39 44 18 60 7 41 37 48 56 24 30 25 48 32 22 64 44 1 48 3961 20 41 39 7 56 2 24 30 46 50 29 35 31 14 20 33 33 5 2 45 10 29 35 4136 44 2 32 14 9 26 64 31 49 3 56 63 37 23 23 54 21 52 30 9 13 18 37 4914 35 43 10 31 14 39 60 13 38 29 54 5 45 3 47 62 11 37 53 30 62 45 34 272 32 58 24 46 44 20 23 43 58 14 18 47 24 25 32 21 59 56 54 8 56 20 60 1732 22 46 14 45 44 10 18 44 52 36 23 41 43 26 60 12 46 37 46 48 20 33 365 11 39 40 58 36 63 41 35 7 45 12 59 4 38 2 4 25 6 64 18 60 2 55 20 4125 4 61 55 44 10 30 60 11 31 Ncb = 2, 1 7 27 63 50 47 15 45 44 26 1 6426 30 PAPR1024: Nifft = 62 38 64 27 26 34 12 45 58 39 9 11 25 59 2.35962048 8 22 54 32 10 10 59 22 34 32 33 30 31 10 PAPR1536: 18 33 30 62 24 558 22 35 28 60 56 16 22 2.9179 52 31 32 48 15 36 7 7 58 14 5 14 35 41PAPR2048: 37 18 22 3 49 22 26 4 6 11 14 64 26 21 2.3596 13 62 6 22 2 5228 55 38 25 48 9 17 54 PAPR4096: 50 15 30 44 36 12 39 54 3 3 22 31 61 532.9864 25 10 33 14 48 42 41 49 37 34 41 54 21 44 20 24 58 2 61 38 41 4611 11 45 39 31 30 8 31 17 4 38 9 26 64 44 53 60 24 49 42 47 16 39 47 1328 19 49 55 42 63 6 46 43 13 32 27 32 27 19 57 47 37 62 53 21 26 11 1653 15 20 33 45 49 62 3 19 12 63 27 28 9 38 38 33 17 57 7 52 15 63 13 133 15 24 5 58 39 41 43 54 17 17 22 34 15 51 16 46 18 64 46 62 8 61 46 4824 57 13 59 15 23 28 51 43 33 55 30 3 15 8 45 25 25 29 10 2 37 50 46 130 23 3 28 59 38 57 2 64 7 26 6 62 49 12 63 54 62 2 29 46 61 27 60 47 2626 13 38 22 62 58 6 17 19 44 9 7 62 35 50 45 4 63 34 17 46 48 34 42 5620 29 2 60 31 53 24 51 64 6 48 57 2 29 50 2 21 8 13 36 19 11 56 31 27 3536 7 59 13 12 31 44 13 54 36 29 5 18 30 15 10 52 9 19 42 48 60 54 28 2262 30 39 32 6 16 43 30 38 43 60 33 8 60 57 52 61 53 8 3 26 27 11 50 2731 16 14 59 16 43 29 52 51 51 12 17 63 17 11 30 46 14 24 51 41 21 6 6322 48 8 39 17 45 39 64 14 33 23 17 9 38 32 36 14 40 5 30 38 40 33 52 119 10 4 46 23 24 52 34 1 16 10 19 53 37 14 62 58 11 30 27 23 4 44 9 51 3839 62 28 44 11 19 43 62 36 19 15 12 38 12 57 28 35 12 31 30 22 31 19 361 64 4 43 58 39 49 53 4 46 49 48 53 31 19 59 53 17 15 17 28 38 47 48 1933 14 13 50 31 27 45 64 22 52 22 11 22 19 58 54 4 25 52 2 55 18 8 33 634 27 62 15 1 50 8 38 13 54 13 63 25 22 17 36 5 54 53 44 30 44 32 57 6350 46 10 57 13 36 35 6 48 7 39 44 26 56 25 18 5 31 34 48 26 30 32 6 3531 59 30 61 56 26 60 41 43 61 32 64 31 56 13 12 35 49 43 16 1 4 59 7 375 47 17 15 49 9 60 10 32 54 41 13 49 42 24 26 35 5 41 28 32 55 45 33 1336 63 50 39 1 49 54 27 13 20 64 37 26 43 64 35 43 40 24 52 54 62 60 8 5714 13 63 64 25 29 35 60 52 26 34 34 31 23 1 46 42 18 24 47 64 29 10 4222 10 34 6 7 43 51 37 39 37 14 34 40 11 57 11 45 13 27 26 33 9 36 13 2745 27 24 34 43 31 44 55 64 36 39 49 16 39 51 26 53 44 12 48 14 52 48 3651 28 9 46 1 61 51 33 19 61 23 52 50 50 14 32 36 52 8 25 17 40 50 42 1324 59 64 64 32 51 57 27 62 12 62 21 61 Ncb = 3, 1 3 57 35 3 5 10 22 4234 39 23 15 59 56 PAPR1536: Nifft = 55 35 18 62 44 4 50 9 51 8 23 29 504 2.4730 1536 9 44 59 27 8 42 14 25 50 39 64 36 6 57 PAPR2048: 60 4 2412 51 7 7 4 30 50 25 15 61 53 2.4867 16 36 47 12 1 21 4 58 1 25 4 26 321 PAPR4096: 32 63 23 2 14 7 41 4 22 22 28 16 48 12 2.4867 56 53 37 29 445 34 54 10 21 59 17 52 53 53 40 4 37 46 31 64 9 57 58 38 35 20 36 41 2332 42 26 15 18 4 9 59 63 7 60 40 14 63 6 59 62 18 1 23 51 30 56 60 12 117 15 63 14 48 23 56 19 50 48 21 44 11 22 23 1 55 15 53 12 43 60 37 3848 40 19 45 36 10 22 56 7 43 15 19 6 54 38 8 7 56 1 7 34 62 25 2 43 3161 19 52 11 49 52 44 64 62 28 61 41 9 63 53 33 58 38 54 7 8 28 44 34 4643 62 6 12 24 18 48 44 37 51 20 27 28 49 12 64 14 38 8 6 9 37 48 59 5926 10 63 43 17 31 1 23 36 25 33 60 43 39 16 1 41 31 10 6 44 41 32 11 3358 6 42 45 41 8 63 56 54 23 30 27 24 12 45 34 5 44 60 48 58 60 56 63 3512 4 24 8 5 3 50 63 27 21 62 37 13 14 46 48 36 30 13 18 57 1 15 48 7 3925 55 31 58 11 38 50 3 44 62 22 59 44 22 17 25 55 36 15 46 16 5 14 1 939 16 8 62 64 28 25 6 17 25 28 21 31 49 2 3 30 59 56 38 53 59 16 56 6 4544 11 56 34 1 21 42 52 50 18 51 3 10 40 50 1 48 29 63 51 20 33 58 18 6448 28 49 8 41 53 38 33 29 51 8 49 41 15 40 59 59 12 48 46 36 13 32 63 828 26 9 19 8 53 11 12 49 24 4 2 40 40 59 18 35 21 3 16 7 33 39 51 58 1027 40 54 4 54 64 2 57 29 23 64 59 32 13 34 20 43 24 35 13 64 25 51 55 246 22 39 12 40 59 56 12 25 26 39 45 23 3 34 10 2 9 36 21 62 14 20 62 1931 58 22 55 4 5 33 13 33 41 41 37 48 16 30 41 22 10 20 40 39 37 16 21 2756 64 50 1 50 36 27 63 59 42 46 44 55 6 12 51 54 27 64 9 43 55 3 58 4134 36 43 36 39 63 57 46 39 40 35 29 38 41 12 2 14 52 60 54 42 30 19 4728 46 46 16 36 64 12 40 53 59 9 53 31 8 57 29 22 22 45 35 38 1 29 54 1663 11 50 24 3 46 6 1 4 21 13 10 36 21 37 63 1 23 55 10 10 19 33 61 25 1123 49 1 16 44 47 4 64 10 54 28 7 31 62 14 10 26 63 2 14 3 14 35 44 30 4833 9 44 8 52 23 42 63 56 14 63 59 58 59 19 20 60 1 18 8 54 35 51 21 4352 5 4 2 9 37 25 8 48 11 37 8 37 8 29 22 16 58 29 25 29 43 45 53 50 5629 45 18 29 61 34 33 61 36 37 1 2 36 33 18 20 17 57 62 42 37 19 16 4 1012 49 4 16 17 22 48 32 56 11 7 19 17 63 14 52 63 12 31 52 45 18 9 30 4056 55 7 34 60 63 46 30 36 64 38 22 31 41 29 17 57 57 16 22 18 44 40 6422 41 45 26 34 51 18 33 17 47 17 60 48 59 53 39 12 14 46 51 35 46 18 1126 53 18 52 57 32 4 57 59 9 1 57 34 40 26 52 31 2 3 7 61 43 31 19 18 6454 36 30 31 18 48 30 6 16 24 50 59 31 41 4 41 46 63 35 28 29 60 38 35 255 47 25 6 18 28 64 10 5 7 55 36 55 26 7 48 28 64 7 42 17 36 27 22 42 5852 34 16 51 41 28 12 44 55 1 34 9 14 50 28 29 39 36 42 14 59 37 22 8 444 35 63 41 41 40 51 64 58 9 58 51 48 33 55 32 32 60 19 19 56 4 16 48 423 10 51 9 58 58 43 11 26 60 1 28 1 60 50 7 44 22 39 62 48 24 38 58 19 927 36 53 33 62 19 61 49 12 21 46 48 5 62 22 21 39 56 56 5 39 32 50 8 244 62 31 23 44 4 35 49 38 37 21 13 35 23 56 45 1 53 16 48 3 37 54 44 3551 57 29 51 53 48 48 55 3 48 21 56 51 12 27 20 57 23 47 60 4 26 52 31 5049 55 63 32 62 24 30 20 20 11 43 47 25 62 15 20 47 41 20 32 13 22 37 401 31 20 43 4 9 45 16 15 64 49 33 40 27 62 60 42 49 7 62 48 45 52 28 4356 12 10 17 1 12 15 39 43 37 7 7 31 36 9 38 62 43 32 35 29 29 2 58 5 217 16 41 3 19 6 50 24 16 43 50 5 36 39 18 24 17 25 26 14 32 55 45 11 5839 52 16 8 25 25 61 52 20 58 12 23 62 16 59 18 2 48 19 18 6 61 63 50 313 6 55 37 19 52 18 3 9 64 50 15 47 32 8 10 25 19 5 62 58 21 38 24 38 5313 7 12 57 4 29 26 26 50 43 49 50 3 59 3 27 13 Ncb = 3, 1 60 62 13 54 6011 41 28 3 15 5 42 7 PAPR1536: Nifft = 62 33 24 29 27 63 24 17 6 9 44 6333 15 2.6508 2048 63 57 1 10 22 22 19 60 55 58 37 60 18 45 PAPR2048: 3539 49 38 62 48 29 19 17 55 6 62 2 38 2.5587 5 50 9 18 61 52 45 7 23 60 639 33 24 PAPR4096: 54 15 16 25 38 58 10 28 32 4 32 3 60 46 2.5587 13 338 50 22 64 29 12 10 5 60 10 55 8 47 33 30 33 38 48 16 9 64 44 58 30 3816 23 27 61 37 55 10 1 37 41 45 20 39 21 16 38 56 34 53 40 26 54 18 4528 1 10 33 29 49 57 22 4 54 51 10 17 5 30 32 59 53 22 45 7 13 60 32 61 844 37 33 3 33 51 51 64 13 8 51 49 49 3 64 10 23 32 17 39 44 58 18 3 2242 4 28 61 54 9 16 48 10 33 1 55 9 16 39 19 63 53 61 9 56 9 64 26 46 3154 14 40 37 10 8 39 63 61 51 46 45 63 40 25 22 23 51 10 29 43 47 28 2129 64 12 13 14 33 57 48 1 31 18 1 57 60 57 40 41 22 23 11 7 23 38 49 2041 12 58 36 9 22 46 40 6 30 63 30 61 53 43 12 24 37 52 34 30 1 26 46 3359 34 62 15 48 52 52 60 64 23 1 27 31 48 34 49 35 51 37 1 62 30 59 34 5330 58 45 55 46 61 6 48 51 64 27 50 10 20 19 21 61 32 51 62 62 11 57 2935 19 48 61 27 42 46 16 31 20 51 24 3 17 2 20 12 12 59 15 55 18 43 46 442 60 54 29 23 32 7 54 38 34 46 35 57 15 32 38 54 28 37 58 30 29 28 36 5342 33 36 19 53 5 1 40 57 43 61 1 63 18 63 64 2 44 33 53 11 9 61 28 9 1648 15 4 9 34 5 43 35 8 4 63 13 33 52 61 61 43 48 56 45 44 26 59 27 49 4953 3 18 9 2 8 4 7 48 39 27 8 37 11 46 10 12 11 34 34 57 54 36 8 31 18 5126 38 18 19 36 14 35 30 30 32 1 34 54 63 16 45 40 36 46 56 63 24 57 6117 58 22 50 23 22 62 9 18 43 47 47 60 41 34 39 53 49 36 61 26 4 13 48 233 28 61 17 19 40 62 59 17 22 34 17 52 27 22 28 24 4 4 40 55 6 3 51 51 3447 49 3 50 55 21 4 61 5 26 9 1 18 48 56 42 58 37 55 27 26 1 64 37 11 6236 6 51 3 5 44 26 33 49 29 3 62 60 49 13 21 63 7 33 14 22 38 42 20 16 1712 12 64 62 45 24 56 29 54 46 33 18 45 53 3 37 2 2 56 10 4 17 40 30 5 6463 41 54 61 41 19 37 15 20 58 27 12 3 28 11 46 32 50 31 32 38 7 4 58 5810 3 1 32 6 56 8 7 13 36 37 16 12 42 56 40 46 42 2 63 14 35 17 33 55 2920 10 55 26 62 11 47 54 30 26 53 54 9 56 61 5 34 47 51 11 17 45 14 58 740 30 51 42 46 20 41 50 35 63 9 59 31 46 64 47 40 60 54 4 11 55 39 43 49 26 50 19 42 3 12 31 11 60 64 33 34 4 7 44 31 14 6 32 42 34 16 57 58 813 40 17 31 45 40 50 33 22 31 43 32 1 13 20 60 15 52 5 35 45 48 45 39 6226 38 13 57 40 8 60 7 54 45 62 35 31 6 53 23 2 43 45 19 40 41 20 27 3116 13 47 18 25 20 61 30 52 31 21 32 10 52 54 27 27 6 57 28 55 15 23 1031 28 57 41 12 4 36 20 24 19 22 60 2 54 64 18 64 60 21 55 39 22 57 52 1014 43 29 55 38 6 25 30 63 1 4 52 32 46 45 64 40 53 41 47 34 46 7 9 21 5114 41 21 25 49 63 3 19 42 41 7 14 44 19 26 22 19 54 32 13 40 61 31 23 4424 6 33 63 35 18 21 6 49 1 7 32 33 4 14 47 13 15 31 4 6 39 61 19 16 1730 15 49 7 44 62 28 27 29 63 23 58 1 49 16 16 16 64 5 31 2 60 7 27 36 714 37 7 27 22 21 41 61 31 55 44 25 59 56 35 8 9 54 35 16 59 60 26 32 2541 9 14 29 3 33 29 10 18 18 55 33 53 10 35 61 28 64 49 12 34 62 5 15 3953 58 28 9 19 57 44 35 11 5 26 53 55 27 35 63 33 46 28 19 54 3 6 30 1245 38 56 15 3 12 45 30 14 55 56 51 60 64 35 45 48 16 5 56 41 44 41 6 3326 20 24 42 44 17 3 42 47 52 8 5 10 13 42 3 37 43 42 27 45 33 59 34 5160 48 4 29 8 30 27 25 3 41 26 46 2 46 58 64 46 35 26 45 33 50 12 31 1423 25 56 19 53 11 34 48 28 20 26 21 30 55 19 64 22 17 8 43 60 35 37 5 1437 4 13 17 54 16 46 50 64 19 56 9 34 21 1 45 9 42 63 30 19 3 44 54 11 586 43 34 10 50 10 47 12 15 31 6 44 47 1 61 32 23 20 15 56 61 7 40 42 5862 61 53 41 55 6 12 11 43 21 1 1 42 56 13 22 43 43 Ncb = 4, 1 10 4 40 2750 47 2 11 58 48 48 53 25 PAPR2048: Nifft = 53 17 58 7 16 25 43 1 27 4362 29 11 15 0.9784 2048 7 32 27 17 34 52 10 61 23 53 24 42 50 58 43 1633 3 35 32 50 9 11 39 37 5 23 29 23 34 31 60 60 14 14 39 32 52 23 16 4615 17 53 15 26 25 12 21 50 30 20 4 35 31 30 52 2 35 40 43 57 26 57 11 4919 21 44 26 19 3 60 9 1 29 27 8 54 58 35 58 50 64 43 49 20 15 27 57 2145 49 17 41 20 45 50 33 18 3 34 46 47 12 63 46 21 62 64 34 50 4 57 25 5652 32 17 13 41 56 10 49 16 35 21 12 50 5 17 15 38 17 2 1 1 10 48 63 8 205 15 47 10 15 25 26 4 41 59 48 36 54 39 39 29 44 60 53 42 21 38 20 12 3953 25 26 10 25 3 20 46 60 62 56 15 61 30 34 38 41 13 12 41 19 50 49 5443 6 15 4 62 4 61 28 56 3 23 20 57 36 4 53 59 40 35 49 29 29 15 15 52 426 36 38 58 42 34 58 39 16 55 17 8 41 45 32 19 33 18 13 19 54 11 34 5558 64 27 44 3 34 37 10 61 15 5 47 59 22 33 15 14 15 32 21 16 47 54 16 419 49 35 57 26 51 39 26 40 48 58 39 56 64 43 49 34 1 52 29 35 27 12 42 2138 37 34 41 5 56 9 50 64 33 47 5 20 8 20 60 59 36 20 13 18 44 31 9 12 330 25 46 4 44 7 13 10 23 10 26 3 30 28 28 47 54 33 4 42 5 47 4 13 42 3049 17 47 15 54 36 47 29 25 39 22 58 59 25 43 60 36 8 53 46 54 59 47 4732 39 25 18 8 35 6 1 41 22 16 40 54 22 26 63 60 16 41 3 5 44 10 46 8 4423 45 44 37 22 51 64 41 58 27 64 33 19 6 43 55 53 35 50 27 27 6 21 24 39 62 53 58 13 59 37 31 25 11 6 38 30 45 37 44 35 51 11 50 10 50 33 51 3542 31 8 36 37 47 8 5 41 39 26 6 17 25 39 23 19 18 34 42 24 48 45 1 60 6437 13 31 41 17 16 25 58 36 36 25 54 14 27 39 58 11 61 3 9 10 25 44 23 5056 30 23 30 40 6 63 51 2 28 56 33 41 52 7 14 29 54 58 41 59 16 6 11 1018 64 55 50 16 15 35 8 39 46 36 22 48 23 45 35 61 50 55 53 8 33 39 35 2914 33 43 44 9 42 44 10 15 44 30 20 42 55 25 39 12 8 2 60 56 20 5 47 62 756 20 9 50 25 18 54 6 51 43 35 63 1 16 27 51 14 11 57 58 34 56 33 58 3325 38 58 30 31 5 31 6 22 34 30 51 16 35 50 44 52 38 53 7 12 49 16 37 3537 64 8 10 39 22 9 9 37 35 33 62 28 18 18 19 12 16 41 14 55 10 62 50 259 44 26 15 28 40 43 32 45 31 31 46 52 39 31 14 9 42 63 47 30 58 2 42 5644 26 21 31 32 35 18 32 21 11 43 9 41 48 36 5 24 44 55 64 55 11 12 27 2030 44 28 63 55 24 64 55 38 23 50 59 21 24 5 34 20 14 58 27 38 62 48 9 2548 4 21 16 25 17 34 43 31 32 40 22 16 8 18 21 12 9 27 32 48 42 49 57 3739 9 10 20 55 62 40 46 16 55 36 47 19 1 28 13 28 29 26 59 11 11 45 9 4419 6 31 7 33 21 30 3 32 21 33 9 46 1 55 62 35 17 45 21 17 2 19 25 51 3053 7 56 19 42 10 20 31 30 39 60 34 27 24 47 13 1 31 4 10 15 16 30 51 1730 47 61 60 51 40 42 50 35 2 21 7 19 40 12 32 35 44 6 22 48 25 52 23 5711 43 3 61 16 47 54 54 15 31 56 32 31 62 49 5 30 10 48 51 24 3 7 6 58 4426 9 58 40 48 7 15 48 50 12 47 32 22 24 36 15 43 46 26 23 63 55 38 27 3156 3 57 18 44 51 61 57 57 51 57 11 55 32 29 39 48 50 11 54 64 50 7 14 2414 54 61 25 32 10 63 6 5 10 25 42 41 4 35 5 50 64 23 31 60 56 20 44 3 523 27 25 51 26 25 62 16 6 55 36 55 41 37 19 16 40 58 60 51 37 43 28 5628 21 13 1 33 23 6 51 30 58 43 39 4 1 37 54 53 14 43 43 14 54 29 7 46 958 30 20 50 29 38 44 36 8 46 46 32 57 8 23 61 34 31 34 41 6 23 40 58 3339 46 20 56 35 25 28 37 56 58 58 56 33 12 48 60 25 8 53 49 15 49 46 38 737 1 2 37 9 43 47 60 43 19 57 29 21 43 9 2 19 53 3 52 7 60 46 10 56 5333 47 3 17 48 61 49 13 14 54 13 18 53 32 5 36 26 35 40 60 17 45 30 25 3747 3 50 52 52 27 4 23 10 9 54 3 24 7 36 7 62 10 2 54 30 15 18 19 31 2657 33 53 12 46 52 29 11 10 50 64 57 56 46 2 22 26 42 54 46 21 44 11 5320 8 23 63 11 10 14 55 61 25 59 2 20 50 56 27 19 42 19 32 53 45 11 34 2561 57 61 1 2 5 22 25 16 38 11 41 40 50 5 28 32 28 53 40 31 26 9 33 3 2961 7 6 33 56 22 21 33 24 34 61 21 14 26 5 36 26 3 41 1 48 47 12 56 41 2358 21 46 20 29 5 36 41 47 49 62 47 9 18 10 49 9 45 62 20 37 46 32 13 863 28 48 29 26 44 63 56 31 31 34 50 43 9 5 61 55 58 3 8 55 54 25 55 6236 40 4 36 2 48 2 45 29 41 49 42 25 51 53 26 35 42 13 39 15 9 12 13 6017 11 31 25 12 15 32 7 51 2 30 55 49 43 42 11 33 48 34 34 52 49 56 11 5830 17 62 47 47 63 60 52 4 17 4 32 25 1 24 53 5 45 59 63 41 42 13 24 5050 48 42 4 38 9 25 64 22 59 59 62 56 50 15 27 51 53 31 22 30 42 52 19 345 27 22 9 16 34 63 43 24 6 16 20 14 52 64 19 13 15 38 63 57 11 23 17 2158 31 24 4 38 19 6 19 48 37 19 2 20 23 61 35 56 25 54 20 54 24 11 11 321 64 17 24 56 7 45 59 1 33 47 54 5 57 38 49 46 18 63 7 21 45 7 60 39 1817 23 49 16 8 57 47 45 57 3 56 55 6 11 42 60 51 36 16 55 59 9 1 53 22 4012 62 62 38 11 56 33 48 18 24 46 49 34 27 48 25 17 31 5 11 25 42 23 3219 29 12 47 27 7 23 61 48 48 55 4 15 16 18 51 25 40 18 53 27 15 4 4 2427 45 45 38 17 10 7 58 21 53 53 32 21 47 32 22 7 29 45 11 41 21 2 57 3954 34 25 25 4 30 34 23 54 34 43 13 29 5 36 20 20 50 54 10 27 58 9 24 836 42 53 Ncb = 4, 1 19 49 4 30 55 48 42 42 28 13 24 58 27 PAPR2048:Nifft = 36 22 60 35 13 12 48 15 36 48 63 50 7 38 2.6136 4096 52 7 61 3231 53 29 33 11 26 40 48 44 5 PAPR4096: 19 6 30 35 40 37 15 12 13 6 13 47 64 2.6136 55 40 3 64 5 25 63 22 8 58 18 5 18 21 9 5 20 41 13 54 62 4121 25 33 50 31 30 20 54 34 57 52 34 24 21 1 19 41 49 54 35 43 4 64 60 1764 43 2 46 52 37 64 32 14 51 32 12 46 41 23 49 5 12 27 15 21 11 4 1 1823 16 23 56 27 2 38 31 2 51 64 18 22 32 31 7 48 64 61 59 42 19 51 46 3243 6 24 39 48 5 44 33 63 2 62 46 46 31 2 62 61 48 41 20 58 34 26 58 1948 54 20 41 37 19 57 6 45 25 57 45 32 9 57 34 17 41 23 52 14 50 18 6 5438 9 50 38 33 17 46 40 44 56 54 9 48 33 55 19 35 57 31 46 21 14 52 34 3220 34 27 53 12 22 37 14 20 52 25 39 5 27 2 63 12 28 37 53 3 15 29 55 938 58 4 62 37 21 51 54 8 52 45 56 62 52 31 64 47 32 59 59 1 22 16 25 3420 9 55 37 12 57 46 1 5 30 2 11 38 40 49 37 32 7 22 50 11 54 26 61 57 4246 18 4 29 51 49 26 22 7 53 50 36 23 60 63 14 16 39 19 58 54 13 39 17 2522 43 59 6 54 30 18 8 34 2 41 56 27 59 49 5 26 28 18 19 26 23 62 17 63 738 59 29 18 46 1 55 45 58 39 31 32 58 10 22 8 12 52 33 5 28 23 58 35 4430 1 19 54 38 63 4 53 9 43 42 4 49 59 46 7 64 61 61 61 4 8 45 24 55 3 4518 44 38 48 7 10 3 22 35 1 24 19 11 32 31 48 13 24 31 39 5 54 33 34 3655 34 31 16 47 18 55 42 21 44 38 36 45 17 29 27 34 15 48 10 9 15 24 5229 37 44 1 27 32 45 48 51 12 54 6 60 54 26 26 30 28 36 14 48 64 61 8 3434 41 9 39 45 61 6 4 28 57 62 51 28 25 24 39 9 4 41 10 39 26 20 58 56 6436 52 28 58 5 9 13 15 20 26 63 28 59 13 31 2 42 19 54 22 10 36 23 60 3926 46 58 64 3 22 52 62 52 47 61 13 52 23 39 26 24 46 18 15 46 49 25 5724 25 29 48 45 54 24 16 34 16 44 50 36 30 29 51 23 57 31 49 54 55 62 639 62 9 29 20 53 13 11 8 1 23 9 39 49 4 58 40 62 27 48 46 17 37 27 47 135 58 47 46 60 55 37 57 52 10 17 1 37 43 33 34 29 17 4 41 20 33 55 57 2952 18 11 5 26 44 33 45 11 54 53 22 20 41 2 17 64 28 64 61 62 47 39 22 6414 4 35 57 48 19 29 30 56 31 2 38 2 1 59 10 49 49 46 43 64 31 9 47 6 4053 37 43 38 29 57 9 62 17 2 4 54 51 43 5 62 42 63 18 22 63 8 11 7 40 4735 44 44 40 48 38 34 16 56 33 15 48 33 17 2 22 34 45 60 51 33 15 30 2727 7 5 44 38 46 44 18 49 31 40 22 21 24 25 35 12 27 30 64 15 64 64 5 4051 2 48 22 38 39 34 42 29 43 43 44 31 21 6 49 41 2 19 56 1 25 38 22 1431 57 25 43 3 24 39 45 26 38 12 11 36 34 19 21 38 43 57 26 49 17 23 2440 54 14 54 12 50 33 49 58 4 29 27 43 41 6 25 40 18 40 8 57 34 47 3 1415 39 2 59 19 12 11 29 20 62 18 17 55 43 29 19 32 33 59 37 40 61 37 5643 3 34 61 51 53 28 24 44 20 21 28 7 9 11 2 38 45 35 22 53 42 22 8 46 3339 42 60 34 29 6 46 55 29 39 35 27 64 14 35 21 11 44 55 1 32 62 26 22 3955 46 54 47 58 2 23 49 23 20 64 36 58 15 18 52 36 47 36 19 49 18 60 2847 47 25 17 5 16 35 17 59 56 10 39 61 56 2 34 38 47 5 14 58 5 13 20 3044 21 6 18 13 40 6 60 11 64 59 4 43 42 23 16 34 33 43 47 64 45 30 27 7 828 46 16 56 50 58 11 25 34 64 48 32 44 18 19 62 17 60 5 33 45 47 5 21 166 55 38 63 63 43 60 46 1 11 24 29 44 62 18 26 60 15 27 29 63 40 29 45 5911 43 6 34 19 38 20 40 29 11 33 36 31 55 61 23 44 37 17 24 52 34 17 5231 20 56 43 56 38 35 51 19 57 26 1 40 1 19 37 58 19 2 33 32 33 15 57 3139 50 3 51 11 49 6 26 59 62 43 44 24 4 58 13 23 57 46 22 60 19 12 53 5123 15 37 47 28 7 17 49 54 21 35 44 21 63 1 56 36 54 24 12 48 33 14 30 740 14 10 7 48 43 44 24 60 39 20 8 57 22 37 57 8 28 61 16 47 37 8 55 2240 30 9 12 15 64 57 46 32 43 16 59 47 40 29 37 42 12 8 51 61 63 29 6 1532 60 39 7 53 41 2 37 2 16 33 64 61 8 41 14 32 47 12 40 16 41 8 20 38 4038 25 57 44 14 8 33 53 30 37 4 14 11 56 35 30 51 18 45 28 46 45 64 1 4 359 14 25 6 34 5 47 53 56 44 28 32 1 46 61 12 46 28 56 7 61 44 16 61 5421 41 51 46 63 63 20 20 62 59 33 54 25 14 28 29 53 62 64 5 53 19 19 6 3422 14 4 57 47 23 42 46 1 35 57 14 30 47 35 30 61 24 34 41 23 22 61 10 1120 57 58 47 7 52 61 15 15 46 64 31 15 58 3 53 61 45 39 54 6 20 54 57 4828 4 43 60 55 1 9 50 16 42 30 40 19 18 32 49 40 39 13 57 16 34 45 5 4331 44 38 64 22 3 42 20 3 61 46 15 47 9 16 53 1 39 2 51 19 23 34 42 8 5442 5 30 36 60 10 42 57 16 12 1 14 41 21 43 60 60 5 63 47 39 51 53 3 4119 8 29 35 63 40 49 22 19 14 48 7 33 27 10 34 58 40 49 63 54 30 28 30 1539 33 12 33 43 30 12 56 2 52 7 4 55 64 7 14 51 20 31 35 45 42 37 27 6424 60 16 15 17 43 32 28 24 17 54 17 7 30 14 7 4 6 48 3 58 1 62 17 16 3840 62 1 38 39 25 15 34 6 10 16 48 11 64 45 20 24 61 64 30 11 6 55 1 3246 16 31 52 40 9 37 58 17 7 64 63 37 1 12 16 23 50 13 32 19 27 55 21 2021 29 56 34 63 10 42 47 31 27 47 51 45 16 12 30 19 63 59 28 24 40 15 1950 21 46 17 36 45 22 49 61 27 29 15 50 56 21 40 13 57 31 24 27 24 43 1823 25 46 40 27 61 35 36 54 26 31 17 37 45 17 6 53 59 33 42 8 63 41 3 6046

A comparison between the existing sequences for CEF of 802.11ay andsuggested 64-PSK sequences is provided by showing temporalcharacteristics in time domain for different cases in FIG. 19 and FIG.20. For the example chart 1900 shown in FIG. 19 Ncb=1, Nifft=512(Nominal) and the temporal characteristics in the time domain are shownby 1901. For the example chart 2000 shown in FIG. 20 Ncb=1, Nifft=1024(Nominal) and the temporal characteristics in the time domain are shownby 2001.

FIG. 21 shows a diagram of an example of flexible TRN generation withOFDM and beams. According to an implementation, TRN may be configurablesuch that the output of OFDM symbol may include repetitions.Accordingly, the TRN sequence may be interleaved in the frequencydomain, such as, before IDFT operation (2001/2002/2003). The beam maychange depending on the interleaving factor. For example, 1× 2110, 2×2120, and 4× 2130 operations are illustrated in FIG. 21. While 1× 2110generates only one TRN 2111 in time, 2× 2120 and 4× 2130 generate two2121/2122 and four 2131/2132/2133/2134 TRN in the time domain,respectively, and the beam on each TRN may be changed. The configurationof TRN may be set through the bit that corresponds to “TRN SubfieldSequence Length” of the 802.11ay EDMG header. The values related to M,N, P described in 802.11ay EDMG header may be a function of theinterleaving factor.

FIG. 22 shows a diagram of an example of a TRN structure of animplementation where the TRN field may include another field, calledlinearity training field (LTRN) 2225 to allow the receiver to estimatethe non-linearity in the link. As shown, PPDU 2200 includes an L-STF(SC) 2201, a L-CEF (SC) 2202, a L-Header (SC) 2203, an EDMG Header (SC)2204, a EDMG STF (OFMD) 2205, an EDMG CEF (OFMD) 2206, a Payload (OFDM)2207, a TRN (OFDM) 2208, TRN Units including TRN Unit 1 2220 through TRNUnit K 2230 where RX TRN-Units per TX TRN Unit Field: K and whichinclude parameters P 2221, N 2222, and M 2223. The LTRN field 2225 maycontain two different reference symbols to estimate AM-AM and AM-PMnonlinearity (not shown). The number of LTRN fields 2225 may beindicated in the header (2203/2204) or it may be a receive capabilitythat is indicated prior to the transmission. The initiator may ask theresponder to send LTRN fields 2225. The LTRN fields 2225 may be afunction of a modulation and coding scheme (MCS) table and the sequencecontent may be a function of the modulation symbols. For example, theelements of the sequence for LTRN field 2225 may be modulation symbols(e.g., 64 QAM). The frequency domain sequence may be precoded with a DFToperation. LTRN signals may be a chirp signal or amplitude-varyingsignal. The feedback for LTRN may indicate the non-linearity function inthe channel (e.g., PA non-linearity).

FIG. 23 shows a diagram of an example transmission and reception of CEFwith phase rotations. The CEF for OFDM PHY in 802.11 ay may be definedas shown in Table 1. The PAPR of such a signal may be further reduced byapplying a set of phase rotations {ϕ₁, ϕ₂, ϕ_(M)} 2302 to the CEFsymbols {x₁, x₂, . . . , x_(M)} 2301 at the input of IDFT via S/P 2306.The phase rotations may be selected such that the PAPR at the output ofIDFT 2303 is minimized. The output of the IDFT 2303 may be provided tothe P/S 2304, the +CP 2305 and transmitted via antenna 2307. FIG. 23includes the receiver structure such that the transmission from antenna2307 is received by receive antenna 2310 and provided to the —CP 2311,then the P/S 2312 and to the DFT 2313. Phase rotations 2314, reciprocalto the phase rotations 2302, may be applied to the output of the DFT2313 and may be provided to the Channel Estimation (CHEST) 2316. Notethat in FIG. 23, M may be the size of CEF and the FFT size mahy beN=M+M_1+M_2. Equivalently, the CEF in Table 1, {x₁, x₂, . . . , x_(M)},may be redefined as {x₁e^(jϕ) ¹ , x₂e^(jϕ) ² , x_(M)e^(jϕ) ^(M) }, whichmay be used as the input to the IFFT directly at the transmitter andused as reference for the CHEST 2316 at the receiver. This concept mayalso be used for the TRN field.

TRN starting point ambiguity may be addressed herein. FIG. 24 is adiagram of an example process for determining the starting point of aTRN field. A PPDU may have padding of either MAC or PHY level paddingthat occupies one or more data blocks/symbols. This may occur in aMU-PPDU where the end of data blocks/symbols for different users have tobe aligned such that the TRN field continues after the aligned datafield. To accurately determine the starting point of a TRN field, thereceiver may need to know the number of data symbols/blocks N.

There may be more than one way to derive N, the number of datasymbols/blocks. A first way to derive N may be based on the PSDU, eitherwith or without MAC padding, and the number of padding symbols/blocks inthe PHY padding. This way may require signaling of two numbers. A secondway to derive N may be based on PSDU length, either with or without MACpassing, and the L header length field, where this way may only requiresignaling of 1 number (i.e., PSDU length). A third way to derive N mayassume a PHY padding which is less than 1 data block/symbol. Thereceiver may determine the N based on L header length. Further, in thisway there may be no required signaling of additional numbers.

In the second and third way of determining the TRN starting point (alsoreferred to as N), N may be derived correctly if the length of datablocks/symbols is greater than or equal to a spoof error limit of 512 Tc(i.e., 1 DMG SC block) such as a DMG SC block 2412 of DMG unit 2410 withDMG preamble 2411. As shown in FIG. 24, the second or third method maybe utilized to determine the starting point of a TRN field. However, forEDMG units 2420 and 2430 with respective EMG preambles 2421 and 2431,the data symbol/block (2422/2432) length is less than 512 Tc and,accordingly, the receiver may not be able determine whether data fieldends at “1st boundary” 2401 or “2nd boundary” 2402, as shown.

To address the TRN starting point determination, the EDMG header mayprovide one or more bits to signal the boundary between data field andTRN field (or at the start of a buffering period between data and TRNfield). This indication may be in an EDMG-header B in a MU-PPDU or theindication may be included in a PPDU transmitted using OFDM PHY in whichcase the data symbol length including guard interval GI may be less than512 Tc. For example, a bit value 0 may indicate the data field ends atthe 1st data symbol/block boundary within the ambiguity region, whilebit value 1 may indicate the data field ends at the 2^(nd) symbol/blockboundary within the ambiguity region.

According to an implementation, there may be a hybrid precoding protocolfor SU-MIMO and MU-MIMO. An EDMG STA may be hybrid precoding capable ifthe hybrid precoding supported field in the STA's EDMG capabilitieselement is one. A hybrid precoding capable STA may support any knownhybrid precoding protocols and/or those described herein. A hybridprecoding capable STA may be SU-MIMO capable, MU-MIMO capable, or both.For example: the hybrid precoding supported field and SU-MIMO supportfield in the STA's EDMG capabilities may be the same and may be set toan affirmative value, such as 1; the hybrid precoding supported fieldand MU-MIMO supported field in the STA's EDMG capabilities element maybe the same and may be set to an affirmative value, such as 1; and/or,the hybrid precoding supported field, the SU-MIMO supported field, andthe MU-MIMO supported field in the STA's EDMG capabilities element maybe the same and may be set to an affirmative value, such as 1.

Hybrid beamforming may be the transmission and reception of multiplespatial streams using a combination of analog beamforming, such as bydetermining appropriate AWVs and digital beamforming, such as bydetermining appropriate spatial mapping matrices, between an SU-MIMOcapable initiator and an SU-MIMO capable responder or between an MU-MIMOcapable initiator and one or more MU-MIMO capable responders. Thebaseband beamformer may be determined based on the DMG antennaconfiguration selected as a result of the SU-MIMO or MU-MIMO beamformingprotocol.

The hybrid beamforming protocol may support digital baseband soundingand hybrid beamforming information feedback for subsequent hybridbeamforming transmission.

The hybrid beamforming protocol can also be used to support thetransmission of a single spatial stream using multiple DMG antennas witha combination of analog beamforming and digital beamforming between anSU-MIMO capable initiator and an SU-MIMO capable responderThe analogbeamformer may be selected during the SU-MIMO beamforming protocol orMU-MIMO beamforming protocol procedures that enable the determination ofthe antenna configuration for the simultaneous transmission of single ormultiple spatial streams from the initiator to the responder(s), or viceversa in the case of SU-MIMO.

Additionally, the hybrid precoding protocol may enable the determinationof the baseband beamformer based on the antenna configuration selectedin the SU-MIMO or MU-MIMO beamforming protocol.

The relationship between the transmitted signal, x, and received signal,Y, can be represented as:

Y _(i,j) =Q _(Br,i,j) H _(BB,i,j) Q _(Bt,i,j) x _(i,j) +Q _(Br,i,j) Q_(Ar,j) n _(i,j) ; H _(BB,i,j) =Q _(Ar,i,j) H _(i,j) Q _(At)

where H_(1,j) is the channel between the transmit DMG antennas andreceive DMG antennas of the jth STA in an MU-MIMO transmission. n_(i,j)is additive white noise at the receiver of the jth STA in an MU-MIMOtransmission. H_(BB,i,j) is the effective baseband channel at thereceiver of the jth STA in an MU-MIMO transmission, i.e., the channelobserved by the baseband processor of the receiver when including theeffect of their DMG antennas at the transmitter and receiver. Q_(At) isthe NTX,A X NTX response of the DMG antennas of the transmitter.Q_(Ar,i,j) is the N_(RX,J) X N_(RX,J,A) response of the DMG antennas atthe receiver of the jth STA in an MU-MIMO transmission. Q_(Bt,i,j) isthe N_(TX) X N_(STS) transmit spatial mapping matrix. Q_(Br,i,j) is theN_(STS,J) X N_(RX,J) receive equalizer at the receiver of the jth STA inan MU-MIMO transmission. x_(i,j) is the transmitted Single User (SU) orMulti-user (MU) MIMO signal. i is the subcarrier Index. For an EDMG SCmode PPDU transmission, i=0; for and EDMG OFDM mode PPDU transmission,0−N_(SR)≤i≤N_(SR)·j=index of jth STA in an MU-MIMO transmission. For anSU-MIMO transmission, j=0.

The hybrid beamforming (HBF) protocol may be a forward HBF protocol or areverse HBF protocol. In the forward HBF protocol the transmitter mayacquire hybrid beamforming information based on feedback from thereceiver derived from the channel in the direction between thetransmitter and receiver. In the reverse HBF, also referred to as animplicit HBF protocol without loss of generality, the transmitter mayacquire hybrid beamforming information directly from the channel in thedirection between the receiver and the transmitter without the need forfeedback. An initiator or responder may initiate a reverse HBF protocolprocedure if the Antenna Pattern Reciprocity subfield in the DMG STACapability Information field of the responder and the Antenna PatternReciprocity subfield in the DMG STA Capability Information field of theinitiator both include an affirmative indication, such as if they areequal to 1.

The HBF protocol may include an announcement phase for forward andreverse HBF protocol that may also be considered a configuration/requestphase, a sounding phase for forward and reverse HBF protocol, a feedbackphase for forward HBF protocol only, and/or a HBF transmission phase.

As further described herein, FIG. 25A-C show examples of forward HBFprotocol frame exchange for SU-MIMO. FIG. 25A shows a forward HBFprotocol for an initiator only. As shown, an initiator 2510 may transmita forward announcement 2511. Upon receipt, a responder 2520 may transmita forward ACK announcement 2521. The initiator 2510 may then transmitforward sounding data and, upon receipt, the responder 2520 may transmita forward feedback 2522. At the last block in FIG. 25A, the initiator2510 may transmit an HBF transmission 2513 based on the forward feedback2522 from the responder 2520.

FIG. 25B shows a forward HBF protocol for a responder only. As shown, aresponder 2540 may transmit a forward announcement 2541 and, uponreceipt, an initiator 2530 may transmit a forward ACK announcement 2531.The responder 2540 may then transmit forward sounding data 2542 and,upon receipt, the initiator 2530 may transmit a forward feedback 2532.At the last block in FIG. 25B, the responder 2540 may transmit an HBFtransmission 2543 based on the forward feedback 2532 from the initiator2530.

FIG. 25C shows a forward HBF protocol for both an initiator and aresponder. As shown, an initiator 2550 may transmit a forwardannouncement 2551. Upon receipt, a responder 2560 may transmit a forwardACK announcement 2561 and, additionally, the responder 2560 may alsotransmit a forward announcement 2562. Upon receipt of the announcementACK 2561, the initiator 2550 may transmit forward sounding data 2553 andupon receipt of the forward announcement 2562, the initiator 2550 maytransmit a forward announcement ACK 2552. The responder 2560 maytransmit forward sounding data 2563 and, upon receipt of the soundingdata 2563, the initiator 2550 may transmit forward feedback 2554. Uponreceipt of the forward sounding data 2553, the responder 2560 maytransmit forward feedback 2564. Upon receipt of the forward feedback2564 from the responder 2560, the initiator 2550 may transmit a HBFtransmission 2555. Upon receipt of the forward feedback 2554 from theinitiator 2550, the responder 2560 may transmit a HBF transmission 2565.

As further described herein, FIG. 26A-D show an examples of reverse HBFprotocol frame exchanges for SU-MIMO. FIG. 26A shows a reverse HBFprotocol for an initiator only. As shown, an initiator 2610 may transmita reverse announcement 2611 and a responder 2620 may transmit anannouncement ACK 2622 and reverse sounding data 2623. The announcementACK 2622 and reverse sounding data 2623 may be transmittedsimultaneously or in the same transmission 2621. The initiator 2610 maytransmit a reverse HBF transmission 2612 upon receiving the announcementACK 2622 and/or reverse sounding data 2623.

FIG. 26B shows a reverse HBF protocol for a responder only. As shown, aresponder 2640 may transmit a reverse announcement 2641 and an initiator2630 may transmit an announcement ACK 2632 and reverse sounding data2633. The announcement ACK 2632 and reverse sounding data 2633 may betransmitted simultaneously or in the same transmission 2631. Theresponder 2640 may transmit a reverse HBF transmission 2642 uponreceiving the announcement ACK 2632 and/or reverse sounding data 2633.

FIG. 26C shows a reverse HBF Protocol for both initiator and responder.As shown, an initiator 2650 may transit a reverse announcement 2651 anda responder 2660 may transmit a reverse announcement ACK 2661 uponreceipt of the reverse announcement 2651. The responder 2660 may alsotransmit a reverse announcement 2662 and the initiator 2650 may transmita reverse announcement ACK 2652 upon receipt of the reverse announcement2662. The responder 2660 may transmit reverse sounding data 2663 uponreceipt of the reverse announcement ACK 2652. The initiator 2650 maytransmit reverse sounding data 2653 upon receipt of the reverseannouncement ACK 2652. Additionally, the initiator 2650 may transmit anHBF transmission 2654 based on the reverse sounding data 2663transmitted by the responder 2660. The responder 2660 may transmit areverse HBF transmission 2664 based on the reverse sounding data 2653transmitted by the initiator 2650.

FIG. 26D shows an alternate reverse HBF protocol for both an initiatorand responder. As shown, an initiator 2670 may transmit a reverseannouncement 2671 and, upon receipt of the reverse announcement 2671, aresponder 2680 may transmit a reverse announcement ACK 2682. Theresponder 2680 may also transmit a reverse announcement 2683 as well asreverse sounding data 2684. The announcement ACK 2632, announcement2683, and reverse sounding data 2684 may be transmitted simultaneouslyor in the same transmission 2681. Upon receipt of the reverseannouncement 2683, the initiator 2670 may transmit a reverseannouncement 2673. The initiator 2670 may also transmit reverse soundingdata 2674. The announcement ACK 2673 and reverse sounding data 2674 maybe transmitted simultaneously or in the same transmission 2672. Theinitiator 2670 may transmit a HBF transmission 2675 based on the reversesounding data 2684 transmitted by the responder 2680. The responder 2680may transmit a HBF transmission 2685 based on the reverse sounding data2674 transmitted by the initiator 2670.

FIG. 27 shows an example of a forward HBF protocol frame exchange forMU-MIMO for both initiator and responder. As shown, an initiator 2710may transmit a first forward announcement 2711, a second forwardannouncement 2712, and a third forward announcement 2713. Responders2720, 2730, and 2740 may optionally transmit forward announcement ACKs2721, 2731, and 2741, respectively, upon receipt of the respectiveforward announcements 2711, 2712, or 2713. It should be noted that theannouncement ACKs may be transmitted successively one after the other ormay be transmitted simultaneously. The initiator 2710 may transmitforward sounding data 2714, 2715 and 2716 to the responders 2720, 2730,and 2740, respectively. Further, the initiator 2710 may transmit polls2717, 2718, and 2719 such that, upon receipt of a respective poll,responders 2720, 2730, and 2740 transmit applicable forward feedback2722, 2732, and 2742. Based on the respective feedback from eachresponder 2720, 2730, and 2740, the initiator 2710 may transmit a HBFtransmission 2750.

FIG. 28 shows an example of reverse HBF protocol for MU-MIMO. As shown,an initiator 2810 may transmit a first reverse announcement 2811, asecond reverse announcement 2812, and a third reverse announcement 2813.Responders 2820, 2830, and 2840 may optionally transmit reverseannouncement ACKs 2821, 2831, and 2841, respectively, upon receipt ofthe respective reverse announcements 2811, 2812, or 2813. It should benoted that the announcement ACKs may be transmitted successively oneafter the other or may be transmitted simultaneously. The initiator 2710may transmit reverse sounding polls 2814, 2815 and 2816 to theresponders 2820, 2830, and 2840, respectively. Upon receipt of thereverse sounding poll 2814, the responder 2820 may transmit reversesounding data 2822. Upon receipt of the reverse sounding poll 2815, theresponder 2830 may transmit reverse sounding data 2832. Additionally,the responder 2830 may also receiver sounding poll 2816 and may transmitreverse sounding data 2834 accordingly. As shown, the responder 2840 maynot transmit reverse sounding data. The initiator 2810 may transmit aHBF transmission based on the reverse sounding data 2822, 2832, and2834.

In the case where the responder may not be able to estimate the feedbackat the time when the initiator requests for the feedback, the respondermay send back an estimate of the minimum amount of time needed for thefeedback to be ready. The initiator may poll the responder at any timeafter this or the responder may autonomously decide to feed back theinformation once it is ready.

In one solution, the initiator may set signal specific times for theresponder(s) to feedback its data. This may be signaled in theannouncement or the sounding signal and eliminates the need for thesounding poll frame.

In one solution, each responder may implicitly estimate the specifictime for which it is to feed back its data. This may be estimated, forexample, by its position in the setup frame or its relative position inthe MU group.

The HBF protocol announcement phase may use an announcementacknowledgement frame exchange between initiator(s) and responder(s) toenable initiator(s) and/or responder(s) to set up their antennaconfigurations to the desired transmit and receive antenna sectors andto indicate the start of an HBF protocol. This announcement phase mayalso include parameters that indicate the type of HBF sounding to beused and the specific HBF information to be sent to the transmitter forHBF transmission. In some cases, an announcement ACK may be implicitlysent to the transmitter of the announcement. Further, if the initiatorand responder are already in the correct configuration and havepreviously set up their HBF protocol information, the announcement phasemay be skipped. The announcement phase may also indicate the time atwhich the actual protocol may start. According to an implementation, theprotocol may be started immediately. According to anotherimplementation, the protocol may start after a delay in time. When theconfiguration is already correct due to, for example, the initiator andresponder previously setting up their HBF protocol information, andthere is no need for an announcement phase, then a QOS Null withtracking setup may be sent or an HBF Control Field may be sent. Whenthere is a MU-MIMO transmission as shown in FIGS. 27 and 28, forexample, the announcement may be sent to multiple users one after theother or simultaneously. The use of a decline to send (DTS), a reverseCT, or an EDMG HBF Announcement ACK frame may ensure a mechanism toallow for transmission in one direction only. Additionally, withassociated signaling there may be a mechanism to allow for a forwardtransmission in one direction and a reverse protocol in the otherdirection.

For a SU-MIMO announcement phase, as shown in FIGS. 25A-C and FIGS.26A-C, the announcement and the announcement acknowledgement may beimplemented by using one or more of a plurality of possible techniquesincluding a Grant frame and Grant ACK frame with control trailers forsignaling, an RTS and clear to send CTS with control trailers forsignaling, and/or a dedicated announcement and announcement ACK withassociated signaling.

In accordance with the the SU-MIMO announcement phase Grant scenario, anEDMG STA transmits a Grant frame with a control trailer to a peer EDMGSTA to indicate the intent to announce the start of a HBF protocol ifthe Grant Required field within the peer STA's EDMG Capabilities elementis affirmative, such as, for example, 1. Alternatively, if the GrantRequired field within the peer STA's EDMG Capabilities is notaffirmative, such as, for example, 0, the STA may determine whether totransmit a Grant frame with a control trailer signaling the start of theHBF protocol and, based on the determination, may transmit a Grant framewith a control trailer signaling the start of the HBF protocol.

In the transmitted Grant frame, the value of the Allocation Durationfield plus the Duration field of the Grant frame may indicate the timeoffset from the PHY-TXEND.indication primitive of the Grant frametransmission when the EDMG STA intends to initiate the start of the HBFprotocol to the peer EDMG STA. For the transmitted Grant frame, aTXVECTOR parameter CONTROL_TRAILER may be set to Present and theparameter CT_TYPE may be set to GRANT_RTS_CTS2Self. The SISO/MIMO fieldmay be set to an affirmative value, such as 1, and the SU/MU MIMO fieldmay be set to a non-affirmative value, such as 0, to indicate that thefollowing HBF sounding is performed in SU-MIMO. The control trailer mayalso indicate the corresponding DMG antenna configuration for theupcoming HBF protocol and the associated HBF protocol sounding andfeedback parameters or HBF sounding. The HBF protocol announcement fieldmay be set to an affirmative value, such as 1, and the parametersgoverning the subsequent HBF protocol may be configured. The parametersmay include the HBF protocol type, the HBF protocol Training Type, theHBF Information Domain, the HBF Information Feedback Type, the HBFFeedback Compression, the HBF Feedback Tap Delay Present, the HBFFeedback Number of Taps Present, the HBF Compressed Nc Index, the HBFCompressed Nr Index, the HBF Compressed Feedback Type, the HBFCompressed CB Info, the HBF Compressed Channel Width, the HBF Feedbackcarrier grouping, and/or the HBF Feedback Carrier Grouping Factor.

If an EDMG STA that receives a Grant frame with a control trailerindicating an HBF protocol announcement to itself is able to perform theHBF protocol at the target time indicated by the Grant frame, the STAmay configure its DMG antennas according to the settings included in thecontrol trailer of the received Grant frame within a time perioddetermined by the value of the Allocation Duration field plus the valueof the Duration field of the received Grant frame starting from thePHY-TXEND.indication primitive of the Grant frame transmission. The STAmay transmit a Grant ACK frame in response to the received Grant frame.For this transmitted Grant ACK frame, the TXVECTOR parameterCONTROL_TRAILER may be set to Present and the parameter CT_TYPE set toGRANT_RTS_CTS2Self. If SU-MIMO is used for the transmission of thereverse direction and HBF sounding is desired, the SISO/MIMO field maybe set to an affirmative value, such as 1, and the SU/MU MIMO field maybe set to a non-affirmative value, such as 0. The control trailer mayalso indicate the corresponding DMG antenna configuration for theupcoming SU-MIMO transmission, the associated HBF protocol sounding, andthe feedback parameters of the upcoming HBF protocol in the reversedirection. The HBF protocol announcement field may be set to anaffirmative value, such as 1, and the parameters governing thesubsequent HBF protocol may be configured. If the STA does not intend toperform HBF sounding in the reverse direction, the SISO/MIMO field maybe set to a non-affirmative value, such as 0.

For the SU-MIMO announcement phase RTS/CTS frames, an EDMG STA maytransmit an RTS frame with a control trailer to a peer EDMG STA toaccess the channel and announce an HBF protocol. This RTS frame may betransmitted using all SU-MIMO sectors by using Cyclic Shift Diversitybetween the transmissions in different sectors. For the transmitted RTSframe, the TXVECTOR parameter CONTROL_TRAILER may be set to Present andthe parameter CT_TYPE set to GRANT_RTS_CTS2Self. The SISO/MIMO field maybe set to an affirmative value, such as 1, and the SU/MU MIMO field maybe set to a non-affirmative value, such as 0, to indicate that thefollowing transmission is performed in SU-MIMO. The control trailer mayalso indicate the corresponding DMG antenna configuration for theupcoming HBF sounding. The HBF protocol announcement field may be set toan affirmative value, such as 1, and the parameters governing thesubsequent HBF protocol may be configured. These parameters may includethe HBF protocol type, the HBF protocol Training Type, the HBFInformation Domain, the HBF Information Feedback Type, the HBF FeedbackCompression, the HBF Feedback Tap Delay Present, the HBF Feedback Numberof Taps Present, the HBF Compressed Nc Index, the HBF Compressed NrIndex, the HBF Compressed Feedback Type, the HBF Compressed CB Info, theHBF Compressed Channel Width, the HBF Feedback carrier grouping, and/orthe HBF Feedback Carrier Grouping Factor.

If an EDMG STA that receives an RTS frame with a control trailerindicating the start of an HBF sounding protocol is able to perform theHBF protocol, it may configure its antennas according to the settingsincluded in the control trailer of the received RTS frame. It may alsotransmit a CTS (e.g., DMG CTS) frame with a control trailer in responseto the received RTS frame. For this transmitted CTS frame, the TXVECTORparameter CONTROL_TRAILER may be set to Present and the parameterCT_TYPE may be set to CTS_DTS.

If SU-MIMO is used for the transmission in the reverse direction, asshown in FIGS. 26A-D, the SISO/MIMO field may be set to an affirmativevalue, such as 1, and the SU/MU MIMO field may be set to anon-affirmative value, such as 0. The CTS frame may be transmitted usingCSD, with a small delay between each sector. The control trailer mayalso indicate the corresponding antenna configuration for the upcomingSU-MIMO transmission in the reverse direction. For this transmitted CTSframe, the TXVECTOR parameter CONTROL_TRAILER may be set to Present andthe parameter CT_TYPE may be set to GRANT_RTS_CTS2SELF_CTS.

If the receiving EDMG STA does not intend to perform HBF sounding in thereverse direction, the SISO/MIMO field may be set to a non-affirmativevalue, such as 0. The CTS frame may be sent using the SISO sector.Alternatively, if the EDMG STA is not able to perform the HBF sounding,it may transmit a DTS frame with a control trailer to the TXOP initiatorto provide further information. The DTS frame may be sent using a SISOtransmission.

All the RTS/CTS procedures may follow the MIMO channel access rules toestablish an HBF protocol.

For the SU-MIMO announcement phase dedicated announcement scenario, adedicated EDMG HBF Announcement Frame and EDMG HBF Announcement ACKFrame may be used for announcement and acknowledgement in the SU HBFprotocol. They may function as a Null Data Packet Announcement and ACK.

An EDMG STA may transmit an EDMG HBF Announcement Frame at the start ofthe HBF protocol to a peer EDMG STA to indicate the intent to initiatean HBF protocol to the peer STA. In the STA info field, the SISO/MIMOfield may be set to an affirmative value, such as 1, and the SU/MU MIMOfield may be set to a non-affirmative value, such as 0, to indicate thatthe following transmission is performed in SU-MIMO. The frame may alsoindicate the corresponding antenna configuration for the upcoming HBFprotocol and the associated HBF protocol sounding and feedbackparameters. The HBF protocol announcement field may be set to anaffirmative value, such as 1, and the parameters governing thesubsequent HBF protocol may be configured. These parameters may includethe HBF protocol type, the HBF protocol Training Type, the HBFInformation Domain, the HBF Information Feedback Type, the HBF FeedbackCompression, the HBF Feedback Tap Delay Present, the HBF Feedback Numberof Taps Present, the HBF Compressed Nc Index, the HBF Compressed NrIndex, the HBF Compressed Feedback Type, the HBF Compressed CB Info, theHBF Compressed Channel Width, the HBF Feedback carrier grouping, and/orthe HBF Feedback Carrier Grouping Factor.

If an EDMG STA that receives an EDMG HBF Announcement Frame indicatingthe start of a HBF protocol to itself is able to perform the HBFprotocol, it may configure its antennas according to the settingsincluded in the control trailer of the received EDMG HBF AnnouncementFrame. It may also transmit an EDMG HBF Announcement ACK Frame inresponse of the received EDMG HBF Announcement Frame. For this ACKframe, the STA info ACK field may be a replica of the STA field in theoriginal transmission. In the case that there is a desire for a changein parameters, the STA ACK field may set its parameters to the desiredvalues. There may be multiple transmissions and receptions of thesefields, until there is a match.

If SU-MIMO is used for the transmission in the reverse direction, asshown in FIGS. 26A-D, the SISO/MIMO field of the STA info request fieldin the EDMG HBF Announcement ACK Frame may be set to an affirmativevalue, such as 1, and the SU/MU MIMO field may be set to anon-affirmative value, such as 0. The EDMG HBF Announcement ACK Framemay be transmitted using all SU-MIMO sectors, with a small delay betweeneach sector. The STA info request field in the EDMG HBF Announcement ACKFrame indicates the corresponding antenna configuration for the upcomingSU-MIMO transmission in the reverse direction.

If SISO is used for the transmission of the reverse direction, theSISO/MIMO field of the STA info request field in the EDMG HBFAnnouncement ACK Frame may be set to a non-affirmative value, such as 0.The EDMG HBF Announcement ACK Frame may be sent using the SISO sector.Alternatively, if the EDMG STA is not able to perform the SU-MIMOtransmission, it may transmit a DTS frame with a control trailer to theTXOP initiator to provide further information. The DTS frame may be sentusing a SISO transmission.

All RTS/CTS procedures may follow the MIMO channel access rules toestablish an HBF protocol.

For MU-MIMO, the announcement and announcement acknowledgement may useone or more of: MU-Grant frames and Grant ACK frames with controltrailers for signaling; Grant frames and Grant ACK frames withMU-control trailers for signaling, where the control trailer contains anMU-MIMO Configuration ID identifying the STAs and the correspondingsectors/spatial streams to be used in the MU transmission; a dedicatedMU-announcement and MU-announcement ACK with associated signaling;and/or an RTS and CTS with MU-control trailers for signaling, where thecontrol trailer contains the MU-MIMO Configuration ID identifying theSTAs and the corresponding sectors/spatial streams to be used in the MUtransmission. For the RTS/CTS scenario, the RTS may be a repeated RTSfor each STA or an MU-RTS that is simultaneously sent to all STAs in theMU-MIMO configuration group, and the CTS may be a repeated CTS for eachin the group or an MU-CTS that is simultaneously sent from all STAs inthe MU-MIMO configuration group.

For the MU-MIMO announcement phase MU-Grant/Grant ACK frames or Grantframes and Grant ACK frames with MU-control trailers for signalingscenarios where there is an HBF protocol to a specific MU-MIMOconfiguration ID, the MU-MIMO initiator may transmit one or moreMU-Grant frames to each responder in the MU configuration ID group. TheTA field of the MU-Grant frame may be set to the BSSID of the initiatorand the RA field may be set to the group address. Note that the termMU-Grant frames may refer to MU-Grant frames with a control trailer of aGrant frame with an MU-control trailer. In the transmitted MU-Grantframe, the value of the Allocation Duration field plus the Durationfield of the Grant frame multiplied by the number of STAs in the MUconfiguration ID group including the SIFS interval between MU-Grantframes may indicate the time offset from the PHY-TXEND.indicationprimitive of the Grant frame transmission when the MU-MIMO initiatorintends to initiate the start of the HBF protocol to the responder EDMGSTAs. For the transmitted MU-Grant frames, the TXVECTOR parameterCONTROL_TRAILER may be set to Present and the parameter CT_TYPE may beset to GRANT_RTS_CTS2Self. The SISO/MIMO field may be set to anon-affirmative value, such as 0, and the SU/MU MIMO field may be set toan affirmative value, such as 1, to indicate that the followingtransmission is performed in MU-MIMO. The control trailer may alsoindicate the corresponding antenna configuration for the upcoming HBFprotocol (by the MU-MIMO configuration ID) and the associated HBFprotocol sounding and feedback parameters. The HBF protocol announcementfield may be set to an affirmative value, such as 1, and the parametersgoverning the subsequent HBF protocol may be configured. Theseparameters may include the HBF protocol type, the HBF protocol TrainingType, the HBF Information Domain, the HBF Information Feedback Type, theHBF Feedback Compression, the HBF Feedback Tap Delay Present, the HBFFeedback Number of Taps Present, the HBF Compressed Nc Index, the HBFCompressed Nr Index, the HBF Compressed Feedback Type, the HBFCompressed CB Info, the HBF Compressed Channel Width, the HBF Feedbackcarrier grouping, and/or the HBF Feedback Carrier Grouping Factor.

If an EDMG STA that receives a Grant frame with a control trailerindicating an HBF protocol announcement to itself is able to perform theHBF protocol at the target time indicated by the Grant frame, the STAmay configure its antennas according to the settings included in thecontrol trailer of the received Grant frame within a time perioddetermined by the value of the Allocation Duration field plus the valueof the Duration field of the received Grant frame starting from thePHY-TXEND.indication primitive of the Grant frame transmission.

The STA may transmit a Grant ACK frame in response of the received Grantframe. For this transmitted Grant ACK frame, the TXVECTOR parameterCONTROL_TRAILER may be set to Present and the parameter CT_TYPE may beset to GRANT_RTS_CTS2Self. Note that if the xx field is set to anaffirmative value, such as 1, then no Grant ACK may be required.

For the MU-MIMO announcement phase RTS/CTS scenario, a MU-MIMO initiatormay transmit one or more RTS frames with a control trailer to responderSTAs to access the channel and announce a HBF protocol. For thetransmitted RTS frame, the TXVECTOR parameter CONTROL_TRAILER may be setto Present and the parameter CT_TYPE may be set to GRANT_RTS_CTS2Self.Note that if the MU-MIMO initiator does not require a reply, it maytransmit a CTS2Self. The SISO/MIMO field may be set to a non-affirmativevalue, such as 0, and the SU/MU MIMO field may be set to an affirmativevalue, such as 1, to indicate that the following transmission isperformed in MU-MIMO. The control trailer may also indicate thecorresponding antenna configuration for the upcoming HBF protocol, bythe MU-MIMO configuration ID, and the associated HBF protocol soundingand feedback parameters. The HBF protocol announcement field may be setto an affirmative value, such as 1, and the parameters governing thesubsequent HBF protocol may be configured. These parameters may includethe HBF protocol type, the HBF protocol Training Type, the HBFInformation Domain, the HBF Information Feedback Type, the HBF FeedbackCompression, the HBF Feedback Tap Delay Present, the HBF Feedback Numberof Taps Present, the HBF Compressed Nc Index, the HBF Compressed NrIndex, the HBF Compressed Feedback Type, the HBF Compressed CB Info, theHBF Compressed Channel Width, the HBF Feedback carrier grouping, and/orthe HBF Feedback Carrier Grouping Factor.

If an EDMG STA that receives an RTS frame with a control trailerindicating the start of a HBF protocol to itself is able to perform theHBF protocol, it may configure its antennas according to the settingsincluded in the control trailer of the received RTS frame. It may alsotransmit a CTS frame with a control trailer in response of the receivedRTS frame. For this transmitted CTS frame, the TXVECTOR parameterCONTROL_TRAILER may be set to Present and the parameter CT_TYPE may beset to CTS_DTS.

If an EDMG STA that receives a CTS2Self frame with a control trailerindicating the start of a HBF protocol to itself is able to perform theHBF protocol, it may configure its antennas according to the settingsincluded in the control trailer of the received RTS frame. In this case,it may then prepare for the sounding phase.

If the EDMG STA is not able to perform the HBF protocol, it may transmita DTS frame with a control trailer to the TXOP initiator to providefurther information. The DTS frame may be sent using a SISOtransmission.

All the RTS/CTS procedures may follow the MIMO channel access rules toestablish an HBF protocol.

According to an implementation, prior to the start of HBF sounding witha set of responder STAs within an MU group, the initiator may includethe MU group within an EDMG Group ID Set element and communicate theresulting element to the STAs in the BSS and may also perform MU-MIMObeamforming with the responders of the MU group. The EDMG STA maytransmit the RTS frame or DMG CTS-to-self frame with a control trailerto the intended MU-MIMO group of responders to indicate the intent toinitiate a HBF sounding protocol with the responders. The RTS and DMGCTS-to-self frame may be transmitted using the MU-MIMO antenna settingobtained through the last successful MU-MIMO beamforming sounding withthe group of responders. The transmitted RTS and DMG CTS-to-self framemay append a control trailer in which the parameter CT_TYPE may be setto GRANT_RTS_CTS2self. In the control trailer, the SISO/MIMO field shallbe set to an affirmative value, such as 1, and the SU/MU MIMO fieldshall be set to an affirmative value, such as 1, to indicate that thereis an upcoming HBF sounding for the MUs. The EDMG Group ID field may beset to the value that identifies the corresponding group of respondersfor the upcoming hybrid beamforming sounding. The RA field of the RTSmay be set to the broadcast MAC address. After transmitting the RTSframe, the initiator may configure it's receive antenna to a quasi-omnireceive pattern to receive the DMG CTS.

An STA that receives an RTS frame addressed to an MU group that the STAbelongs to may transmit a DMG CTS frame back to the initiator employingthe most recent SISO antenna configuration used between the responderand the initiator. The DMG CTS frame may be transmitted a SIFS intervalfollowing the reception of the RTS frame. The TA field of the DMG CTSmay be set to the broadcast MAC address and the Scrambler Initializationfield in the PHY header may be set to the same value as the ScramblerInitialization field of the PPDU that contained in the received RTSframe. Following transmission of the DMG CTS, the responder may thenconfigure its antennas based on the antenna setting obtained during thelast MU-MIMO beamforming sounding for the MU group. The HBF sounding maybegin a SIFS interval following the reception or expected reception ofthe DMG CTS frame by the initiator.

An STA that receives a DMG CTS-to-self frame addressed to an MU groupthat the STA belongs to may configure its antennas based on the antennasetting obtained during the last successful MU-MIMO beamforming soundingfor the MU group. The hybrid beamforming sounding begins a SIFS intervalfollowing the end of the DMG CTS-to-self frame transmission by theinitiator

For the MU-MIMO announcement phase dedicated MU-announcement scenario, adedicated EDMG HBF Announcement Frame and ACK Frame may be used forannouncement and acknowledgement in a MU HBF protocol. These mayfunction as a Null Data Packet Announcement and ACK.

According to an implementation, a sounding phase, also known as thetraining phase, may follow the announcement phase, if an announcementphase is implemented. For the sounding phase of hybrid precoding for SUand MU MIMO, sounding signals may be sent to the STA(s) for measurementusing the CEF or TRN subfields to or from the transmitter to enable theSTA to measure the baseband channel. The sounding phase may havedifferent types of sounding including Beam Refinement Phase (BRP)sounding, beam tracking sounding, and/or CEF based sounding with QoSNull frames with the CEF dimensioned for the SU and the MU antennaconfiguration. The HBF protocol sounding type field in the CT may signalthe type of sounding by, for example, 1, 2, and 3, respectively.

For BRP sounding in a SU-MIMO forward scenario for both initiator andresponder, as shown in FIGS. 26C-D, the initiator may initiate thesounding phase at MBIFS following reception of the Announcement ACKframe from the responder. In the initiator sounding subphase, theinitiator may transmit EDMG BRP-RX/TX packets to the responder. EachEDMG BRP-RX/TX packet may be separated by a SIFS for the desiredconfiguration. Each transmitted EDMG BRP-RX/TX packet may be used totrain one or more transmit sectors and, for each transmit sector, totrain a number of receive AWVs, for the configuration setup in theannouncement frame. In each EDMG BRP-RX/TX packet, the initiator mayinclude, for each selected transmit sector, TRN subfields in the TRNfield of the PPDU for the responder to receive AWV sounding. For eachEDMG BRP-RX/TX packet, the TXVECTOR parameter EDMG_TRN_LEN may be set toa value greater than zero, and the parameters RX_TRN_PER_TX_TRN andEDMG_TRN_M may be set to the values of the L-TX-RX and EDMG TRN-Unit Msubfields received in the feedback from the responder in the SISO phase,respectively. The initiator may transmit each EDMG BRP-RX/TX packet totrain multiple TX DMG antennas simultaneously by using the TRNsubfields, which may reduce sounding time. The TX Antenna Mask field ofeach EDMG BRP-RX/TX packet may indicate the TX DMG antenna(s) that isbeing used by the initiator to transmit the EDMG BRP-RX/TX packet. TheBRP CDOWN field of each EDMG BRP-RX/TX packet may indicate the number ofremaining EDMG BRP RX/TX packets to be transmitted by the initiator inthe initiator SMBT subphase.

If the responder indicates that it will use SU-MIMO in the oppositedirection, such as from the responder to the initiator, during theannouncement phase, then the responder may initiate sounding subphase atan appropriate interframe spacing such as, for example, SIFS or MBIFS,following the reception of an EDMG BRP-RX/TX packet with the BRP CDOWNfield set to a non-affirmative value, such as 0, from the initiator. Inthe responder sounding subphase, the responder may transmit EDMGBRP-RX/TX packets to the initiator. Each EDMG BRP-RX/TX packet may beseparated by a SIFS. For each EDMG BRP-RX/TX packet, the TXVECTORparameter EDMG_TRN_LEN may be set to a value greater than zero, and theparameters RX_TRN_PER_TX_TRN and EDMG_TRN_M may be set to the values ofthe L-TX-RX and Requested EDMG TRN-Unit M subfields in the MIMO BF Setupframe received from the initiator in the SU-MIMO BF setup subphase,respectively. The responder may transmit each EDMG BRP-RX/TX packet totrain multiple TX DMG antennas simultaneously by using the TRNsubfields, which may reduce sounding time. The TX Antenna Mask field ofeach EDMG BRP-RX/TX packet may indicate the TX DMG antenna(s) that isbeing used by the responder to transmit the EDMG BRP-RX/TX packet. TheBRP CDOWN field of each EDMG BRP-RX/TX packet may indicate the number ofremaining EDMG BRP RX/TX packets to be transmitted by the responder inthe responder SMBT subphase.

According to an implementation, if the sounding is for the initiatoronly or responder only, only the STA sounding its channel may send theBRP.

According to an implementation, for BRP sounding in a SU-MIMO reversescenario, as shown in FIGS. 26A-D, the announcement and announcementACKs may be completed in both directions and the sounding commences anMBIFS duration after the completion of the announcement ACK to theresponder. The responder may transmit EDMG BRP-RX/TX packets to theinitiator based on the fixed configuration of the forward link. Ifindicated, the initiator may then transmit an EDMG BRP-RX/TX to theresponder based on the fixed configuration of the reverse link. Inanother example, the announcement and announcement ACKs may not becompleted in both directions and the sounding commences an MBIFSduration after the reception of the announcement ACK to the initiator.The responder may transmit EDMG BRP-RX/TX packets to the initiator basedon the fixed configuration of the forward link. If indicated, theinitiator may send an announcement ACK to the responder and then theinitiator may then transmit an EDMG BRP-RX/TX to the responder based onthe fixed configuration of the reverse link.

For BRP sounding in a MU-MIMO forward scenario, as shown in FIG. 27, theinitiator may initiate the HBF sounding subphase an MBIFS following thetransmission of the Announcement ACK frame. In the HBF soundingsubphase, the initiator may transmit one or more EDMG BRP-RX/TX packetsto the remaining responders in the MU group. Each EDMG BRP-RX/TX packetmay be separated by a SIFS. Each transmitted EDMG BRP-RX/TX packet maybe used to train one or more transmit sectors and, for each transmitsector, to train a number of receive AWVs. In each EDMG BRP-RX/TXpacket, the initiator may include, for each selected transmit sector,TRN subfields in the TRN field for remaining responders to performreceive AWV sounding. For each EDMG BRP-RX/TX packet, the TXVECTORparameter EDMG_TRN_LEN may be set to a value greater than zero. Theparameters RX_TRN_PER_TX_TRN and EDMG_TRN_M may be set in such a mannerthat the number of TRN subfields included in the TRN field used forreceive AWV(s) sounding is the maximum number of receive sectors acrossall the remaining responders based on the L-TX-RX subfields and the EDMGTRN-Unit M subfields in the feedback from all the remaining respondersin the SISO phase. The initiator may transmit each EDMG BRP-RX/TX packetto train multiple TX DMG antennas simultaneously using TRN subfields toreduce the sounding time. The TX Antenna Mask field of each EDMGBRP-RX/TX packet may indicate the TX DMG antenna(s) that is being usedby the responder to transmit the EDMG BRP-RX/TX packet. The BRP CDOWNfield of each EDMG BRP-RX/TX packet may indicate the number of remainingEDMG BRP RX/TX packets to be transmitted by the initiator in the HBFsounding subphase.

For BRP sounding in a MU-MIMO reverse scenario, as shown in FIG. 28, theinitiator may initiate an HBF protocol reverse sounding subphase anMBIFS following the transmission of the last Announcement frame orreceipt of the last announcement ACK if required. In the HBF protocolreverse sounding subphase, the initiator may transmit a MIMO BF Pollframe with the Poll Type field set to an affirmative value, such as 1,to each remaining responder in the MU Configuration ID group. Each MIMOBF Poll frame may be sent using the DMG control mode. The TA field ofeach MIMO BF Poll frame may be set to the BSSID of the initiator and theRA field may be set to the MAC address of the corresponding responder.Each MIMO BF Poll frame may carry the dialog token in the Dialog Tokenfield that identifies the MU-MIMO BF sounding. Additionally, in order toreduce sounding time, the initiator may reduce the number of TRNsubfields used for receiving AWV sounding in the following EDMGBRP-RX/TX packets transmitted by each remaining responder based on theSNRs of transmit sectors collected from each remaining responder in theSISO phase. The L-TX-RX subfield and the Requested EDMG TRN-Unit Msubfield of each MIMO BF Poll frame may indicate the number of TRNsubfields required for receiving AWV sounding in the following EDMGBRP-RX/TX packets to be transmitted by the corresponding responder. TheRequested EDMG TRN-Unit P subfield of each MIMO BF Poll frame mayindicate the number of TRN subfields in a TRN-Unit that need to betransmitted with the same AWV as the preamble and Data field in thefollowing EDMG BRP-RX/TX packets to be transmitted by the correspondingresponder.

Upon receiving a MIMO BF Poll frame for which a remaining responder isthe addressed recipient, the responder may transmit one or more EDMGBRP-RX/TX packet(s) to the initiator, where the TXVECTOR parameterEDMG_TRN_LEN may be set to a value larger than zero, and the parametersRX_TRN_PER_TX_TRN, EDMG_TRN_M and EDMG_TRN_P may be set to the values ofthe L-TX-RX field, the Requested EDMG TRN-Unit M field and the RequestedEDMG TRN-Unit P field in the corresponding MIMO BF Poll frame receivedfrom the initiator, respectively. Additionally, the responder maytransmit each EDMG BRP-RX/TX packet to train multiple TX DMG antennassimultaneously using TRN subfields to reduce sounding time. The TXAntenna Mask field of each EDMG BRP-RX/TX packet may indicate the TX DMGantenna(s) that are being used by the responder to transmit the EDMGBRP-RX/TX packet. The BRP CDOWN field of each EDMG BRP-RX/TX packet mayindicate the number of remaining EDMG BRP RX/TX packets to betransmitted by the responder.

Each MIMO BF Poll frame and each EDMG BRP-RX/TX packet may be separatedby a SIFS.

For tracking sounding in a SU-MIMO forward scenario the initiator mayinitiate the sounding phase an MBIFS following reception of theAnnouncement ACK frame from the responder. The initiator may transmit aframe, such as a QOS Null frame with the DMG header and EDMG header-Afields setting up the EDMG initiator transmit beam tracking procedurewith HBF Feedback requested. The feedback used may be based on the HBFfeedback requested in the announcement frame.

According to an implementation for tracking sounding in a SU-MIMOreverse scenario, the announcement and announcement ACKs may becompleted in both directions and the sounding may commence an MBIFSduration after the completion of the announcement ACK to the responder.The responder may transmit a frame (e.g., a QOS Null frame) with the DMGheader and EDMG-header-A setting up an EDMG initiator to receive beamtracking. Alternatively, the initiator may transmit a frame (e.g., a QOSnull frame) with the DMG header and EDMG header-A for setting up, andthe EDMG responder may transmit the beam tracking procedure.

If indicated, the initiator may then transmit a frame (e.g., a QOS Nullframe) with the DMG header and EDMG-header-A setting up an EDMGinitiator to receive beam tracking. Alternatively, the responder maytransmit a frame (e.g. a QOS null frame) with the DMG header and EDMGheader-A for setting up and the EDMG responder may transmit a beamtracking procedure.

According to another implementation for tracking sounding in a SU-MIMOreverse scenario, the announcement and announcement ACKs may not becompleted in both directions and the sounding may commence an MBIFSduration after the reception of the announcement ACK to the initiator.The responder may transmit a frame, such as a QOS Null frame with theDMG header and EDMG-header-A setting up an EDMG initiator to receivebeam tracking. Alternatively, the initiator may transmit a frame, suchas a QOS null frame, with the DMG header and EDMG header-A for settingup and the EDMG responder may transmit a beam tracking procedure.

If indicated, the initiator may send an announcement ACK to theresponder and then the initiator may then transmit a frame, such as aQOS Null frame, with the DMG header and EDMG-header-A setting up an EDMGinitiator to receive beam tracking. Alternatively, the responder maytransmit a frame, such as a QOS Null frame, with the DMG header and EDMGheader-A for setting up and the EDMG responder may transmit a beamtracking procedure.

For CEF sounding in a forward scenario the initiator may initiate thesounding phase an MBIFS following reception of the Announcement ACKframe from the responder. The initiator may transmit a frame, such as aQOS Null frame, with the CEF field set to the forward channelconfiguration requested in the announcement. The channel measurementsmay be made from the CEF field. The feedback used may be based on theHBF feedback requested in the announcement frame.

According to an implementation of CEF sounding in a reverse scenario,the announcement and announcement ACKs may be completed in bothdirections and the sounding may commence an MBIFS duration after thecompletion of the announcement ACK to the responder. The responder maytransmit a frame, such as a QOS Null frame, with the CEF field set tothe forward channel configuration requested in the announcement. Ifindicated, the initiator may then transmit a frame, such as a QOS Nullframe, with the CEF field set to the forward channel configurationrequested in the announcement.

According to another implementation of CEF sounding in a reversescenario, the announcement and announcement ACKs may not be completed inboth directions and the sounding commences an MBIFS duration after thereception of the announcement ACK to the initiator. The responder maytransmit a frame, such as a QOS Null frame, with the CEF field set tothe forward channel configuration requested in the announcement.

If indicated, the initiator may send an announcement ACK to theresponder and then the initiator may then transmit a frame, such as aQOS Null frame, with the CEF field set to the forward channelconfiguration requested in the announcement.

The tracking and the CEF techinques may be used for MU HBF protocolsounding.

According to implementations disclosed herein, the feedback phase ofhybrid precoding for SU and MU MIMO may only be activated in the forwardHBF protocol to send back the HBF information to the transmitter for usein an HBF transmission. The feedback may be primarily affected by one ormore of at least three parameters in the CT or the HBF control elementincluding HBF Information Feedback Type such as channel feedback orprecoder feedback, HBF Feedback Compression, such as compressed oruncompressed, and HBF Information Domain, such as time domain orfrequency domain. This feedback may be implemented in the SC PPDUs andthe OFDM PPDUs as noted in Tables 4A and 4B below.

TABLE 4A SC PPDU HBF In- HBF HBF In- formation Feedback formationFeedback Compres- Domain Type sion Comment Time Channel No ChannelFeedback Time Channel Yes Channel Feedback with compression. Use thecompression framework to send back the effective channel. Time PrecoderNo Feedback for time domain precoder with no compression Time PrecoderYes Feedback for time domain precoder with compression framework.Frequency Channel No N/A Frequency Channel Yes N/A Frequency Precoder NoN/A Frequency Precoder Yes N/A

TABLE 4B OFDM PDU HBF In- HBF HBF In- formation Feedback formationFeedback Compres- Domain Type sion Comment Time Channel No ChannelFeedback Time Channel Yes Channel Feedback with compression. Use thecompression framework to send back the effective channel. Time PrecoderNo N/A Time Precoder Yes N/A Frequency Channel No Feedback for frequencydomain channel. May be converted to frequency and then used to designHBF. Frequency Channel Yes Feedback for compressed frequency domainchannel. May be converted to frequency and then used to design HBFFrequency Precoder No Feedback for uncompressed precoder. FrequencyPrecoder Yes Feedback for compressed precoder.

As noted in Table 4A and 4B, there may be different categories offeedback that may be used, such as, Channel Feedback (SU MIMO/SC) whichmay use MIMO feedback, Channel Feedback (MU MIMO/SC) which may use MIMOfeedback, Precoder Feedback (SU-MIMO/SC) which may use 802.11n/acfeedback framework (e.g., Nc, Nv, etc.) but for time domain channelelements, Precoder Feedback (MU-MIMO/SC) which may use 802.11n/acfeedback framework (e.g., Nc, Nv, etc.) but for time domain channelelements, Channel Feedback (SU MIMO/OFDM), Channel Feedback (MUMIMO/OFDM), Precoder Feedback (SU-MIMO/OFDM) which may use 11n//11acfeedback, and/or Precoder Feedback (MU-MIMO/OFDM), which may use11n/11ac feedback.

According to implementations disclosed herein, for HBF transmission, ifchannel feedback is used or if the channel is based on reciprocity, thenthe transmitter may use a channel to design a digital beamformer.Additionally, if an HBF transmission is based on precoder feedback, thenthe transmitter may use the precoder, unchanged.

FIG. 29 shows an example of a beamforming capability field 2900. Row2910 shows the bit locations for the example beamforming capabilityfield and row 2920 shows the number of bits per field. The examplebeamforming capability field 2900 includes Request BRP SC blocks (5bits) 2931, a MU-MIMO Supported field (1 bit) 2932, a SU-MIMO Supportedfield (1 bit) 2933, a Grant Required field (1 bit) 2934, a NoRSSSupported field (1 bit) 2935, a HBF Supported field (1 bit) 2936, a SUMIMO HBF Supported field (1 bit) 2937, a MU-MIMO HBF Supported field (1bit) 2938, and a reserved field (4 bits) 2939. The HBF Supported fieldmay be set to an affirmative value, such as 1, to indicate that the STAsupports the HBF protocol and may be set to a non-affirmative value,such as 0, to indicate that the STA does not support the HBF protocol.The SU-MIMO HBF Supported field may be set to an affirmative value, suchas 1, to indicate that the STA supports SU-MIMO and the HBF protocol andmay be set to a non-affirmative value, such as 0, to indicate that theSTA does not support the HBF protocol. The MU MIMO HBF Supported fieldmay be set to an affirmative value, such as 1, to indicate that the STAsupports MU-MIMO and the HBF protocol and may be set to anon-affirmative value, such as 0, to indicate that the STA does notsupport the HBF protocol.

Table 5 shows an example of the control trailer in HBF.

TABLE 5 Control Trailer in HBF Number Start Field of bits bitDescription Channel 1 0 Aggregation BW 8 1 Primary Channel 3 9 NumberSISO/MIMO 1 12 Set to a non-affirmative value, such as 0, to indicatethat the following transmission from this STA is performed in SISO. Setto an affirmative value, such as 1, to indicate that the followingtransmission from this STA is performed in MIMO. SU/MU MIMO 1 13 Set toa non-affirmative value, such as 0, to indicate SU- MIMO, and set to anaffirmative value, such as 1, to indicate MU-MIMO. Reserved whenSISO/MIMO is set to a non- affirmative value, such as 0. Number of SS 314 The value of this field plus one may indicate the number of SSstransmitted to the EDMG STA that is the recipient of the controltrailer. Reserved if SISO/MIMO is set to a non- affirmative value, suchas 0. TX Sector 6 17 This field may indicate the sector that thetransmitter of this ID for SS1 control trailer uses for SS1. Reserved ifSISO/MIMO is set to a non-affirmative value, such as 0. TX DMG antenna 223 This field may indicate the DMG antenna that the transmitter ID forSS1 of this control trailer uses for SS1. Reserved if SISO/MIMO is setto a non-affirmative value, such as 0. RX DMG antenna 2 25 This fieldmay indicate the DMG antenna that the recipient ID for SS1 of thiscontrol trailer uses for SS1. Reserved if SISO/MIMO is set to anon-affirmative value, such as 0. TX Sector 6 27 This field may indicatethe sector that the transmitter of this ID for SS2 control trailer usesfor SS2. Reserved if SISO/MIMO is set to a non-affirmative value, suchas 0. TX DMG antenna 2 33 This field may indicate the DMG antenna thatthe transmitter ID for SS2 of this control trailer uses for SS2.Reserved if SISO/MIMO is set to a non-affirmative value, such as 0. RXDMG antenna 2 35 This field may indicate the DMG antenna that therecipient ID for SS2 of this control trailer uses for SS2. Reserved ifSISO/MIMO is set to a non-affirmative value, such as 0. TX Sector 6 37This field indicates the sector that the transmitter of this ID for SS3control trailer uses for SS3. Reserved if SISO/MIMO is set to anon-affirmative value, such as 0. TX DMG antenna 2 43 This field mayindicate the DMG antenna that the transmitter ID for SS3 of this controltrailer uses for SS3. Reserved if SISO/MIMO is set to a non-affirmativevalue, such as 0. RX DMG antenna 2 45 This field may indicate the DMGantenna that the recipient ID for SS3 of this control trailer uses forSS3. Reserved if SISO/MIMO is set to a non-affirmative value, such as 0.TX Sector 6 47 This field may indicate the sector that the transmitterof this ID for SS4 control trailer uses for SS4. Reserved if SISO/MIMOis set to a non-affirmative value, such as 0. TX DMG antenna 2 53 Thisfield may indicate the DMG antenna that the transmitter ID for SS4 ofthis control trailer uses for SS4. Reserved if SISO/MIMO is set to anon-affirmative value, such as 0. RX DMG antenna 2 55 This field mayindicate the DMG antenna that the recipient ID for SS4 of this controltrailer uses for SS4. Reserved if SISO/MIMO is set to a non-affirmativevalue, such as 0. TX Sector 6 57 This field may indicate the sector thatthe transmitter of this ID for SS5 control trailer uses for SS5.Reserved if SISO/MIMO is set to a non-affirmative value, such as 0. TXDMG antenna 2 63 This field may indicate the DMG antenna that thetransmitter ID for SS5 of this control trailer uses for SS5. Reserved ifSISO/MIMO is set to a non-affirmative value, such as 0. RX DMG antenna 265 This field may indicate the DMG antenna that the recipient ID for SS5of this control trailer uses for SS5. Reserved if SISO/MIMO is set to anon-affirmative value, such as 0. TX Sector 6 67 This field may indicatethe sector that the recipient of this ID for SS6 control trailer usesfor SS6. Reserved if SISO/MIMO is set to a non-affirmative value, suchas 0. TX DMG antenna 2 73 This field may indicate the DMG antenna thatthe transmitter ID for SS6 of this control trailer uses for SS6.Reserved if SISO/MIMO is set to a non-affirmative value, such as 0. RXDMG antenna 2 75 This field may indicate the DMG antenna that therecipient ID for SS6 of this control trailer uses for SS6. Reserved ifSISO/MIMO is set to a non-affirmative value, such as 0. TX Sector 6 77This field may indicate the sector that the transmitter of this ID forSS7 control trailer uses for SS7. Reserved if SISO/MIMO is set to anon-affirmative value, such as 0. TX DMG antenna 2 83 This field mayindicate the DMG antenna that the transmitter ID for SS7 of this controltrailer uses for SS7. Reserved if SISO/MIMO is set to a non-affirmativevalue, such as 0. RX DMG antenna 2 85 This field may indicate the DMGantenna that the recipient ID for SS7 of this control trailer uses forSS7. Reserved if SISO/MIMO is set to a non-affirmative value, such as 0.TX Sector 6 87 This field may indicate the sector that the recipient ofthis ID for SS8 control trailer uses for SS8. Reserved if SISO/MIMO isset to a non-affirmative value, such as 0. TX DMG antenna 2 93 Thisfield indicates the DMG antenna that the transmitter of ID for SS8 thiscontrol trailer uses for SS8. Reserved if SISO/MIMO is set to anon-affirmative value, such as 0. RX DMG antenna 2 95 This fieldindicates the DMG antenna that the recipient of ID for SS8 this controltrailer uses for SS8. Reserved if SISO/MIMO is set to a non-affirmativevalue, such as 0. HBF protocol 1 96 Set to a non-affirmative value, suchas 0, to indicate that this announcement control trailer is not a HBFannouncement. Set to an affirmative value, such as 1, to indicate thatthis control trailer is a HBF protocol announcement. HBF protocol 1 97The value of this field may indicate the type of HBF protocol typerequested. Set to a non-affirmative value, such as 0, to indicate aForward HBF Protocol. Set to an affirmative value, such as 1, toindicate a Reverse HBF announcement. Reserved if HBF protocol is set toa non-affirmative value, such as 0. HBF protocol 2 98 The value of thisfield may indicate the type of sounding to Sounding Type be used for theHBF protocol. 0: BRP sounding, 1. Beam tracking sounding 2. CEF basedsounding. 3. Reserved. The Beam Tracking and CEF based sounding may usesuitable frames such as the QOS Null. Reserved if HBF protocol is set toa non-affirmative value, such as 0. HBF Information 1 100 The value ofthis field may indicate whether the HBF Domain Information is in thefrequency domain (more suitable for OFDM PPDUs) or in the time domain(more suitable for SC PPDUs but can be post-processed for OFDM PPDUs)Set to a non-affirmative value, such as 0, to indicate Time Domaintraining, and set to an affirmative value, such as 1, for FrequencyDomain training. Reserved if HBF protocol is set to a non-affirmativevalue, such as 0. HBF Information 1 101 The value of this field mayindicate the type of HBF Feedback Type information. Set to anon-affirmative value, such as 0, to indicated Channel Feedback, and setto an affirmative value, such as 1, to indicate Precoder Feedback.Reserved if HBF protocol is set to a non-affirmative value, such as 0.HBF Feedback 1 The value of this field may indicate if the HBFinformation is Compression compressed or uncompressed. Set to anon-affirmative value, such as 0, to indicate non-compressed HBFinformation, and set to an affirmative value, such as 1, to indicateCompressed HBF information. Reserved if HBF protocol is set to anon-affirmative value, such as 0. HBF Feedback 1 102 If the feedbacktype field is set to a non-affirmative value, Tap Delay such as 0, andthe HBF protocol field is set to an affirmative Present value, such as1, and the HBF protocol type is set to a non- affirmative value, such as0, this subfield is set to an affirmative value, such as 1, to indicatethat the Tap Delay subfield is present as part of the HBF information.This subfield is set to a non-affirmative value, such as 0, in all othercases. Reserved if HBF protocol is set to a non- affirmative value, suchas 0. HBF Feedback 2 103 If the Tap Delay Present subfield is set to anaffirmative Number of Taps value, such as 1, this subfield indicates theNumber of Present taps in each channel measurement: 0x0 - 1 tap 0x1 - 4× NCB + 1 taps 0x2 - 14 × NCB + 1 taps 0x3 - 62 × NCB + 1 taps Where NCBis the integer number of contiguous 2.16 GHz channels over which themeasurement was taken. Reserved if HBF protocol is set to anon-affirmative value, such as 0. HBF Compressed 3 105 If the HBFcompression subfield is set to an affirmative Nc Index value, such as 1,this subfield indicates the number of columns, Nc, in the compressedbeamforming feedback matrix minus 1: Set to a non-affirmative value,such as 0, for Nc = 1 Set to an affirmative value, such as 1, for Nc = 2. . . Set to 7 for Nc = 8 Reserved if HBF protocol is set to anon-affirmative value, such as 0. HBF Compressed 3 108 If the HBFcompression subfield is set to an affirmative Nr Index value, such as 1,this subfield indicates the number of rows, Nr, in the compressedbeamforming feedback matrix minus 1: Set to a non-affirmative value,such as 0, for Nr = 1 Set to an affirmative value, such as 1, for Nr = 2. . . Set to 7 for Nr = 8 Reserved if HBF protocol is set to anon-affirmative value, such as 0. HBF Compressed 1 111 If the HBFcompression subfield is set to an affirmative Feedback Type value, suchas 1, this subfield indicates if the feedback is for SU-MIMO or MU-MIMOtransmission. Set to a non- affirmative value, such as 0, to indicateSU-MIMO and set to an affirmative value, such as 1, to indicate MU-MIMO.Reserved if HBF protocol is set to a non-affirmative value, such as 0.HBF Compressed 1 112 If the HBF compression subfield is set to anaffirmative CB Info value, such as 1, this subfield indicates the sizeof codebook entries: If Compressed Feedback Type field is SU: Set to anon-affirmative value, such as 0, for 2 bits for ψ, 4 bits for ϕ Set toan affirmative value, such as 1, for 4 bits for ψ, 6 bits for ϕ IfCompressed Feedback Type field is MU: Set to a non-affirmative value,such as 0, for 5 bits for ψ, 7 bits for ϕ Set to an affirmative value,such as 1, for 7 bits for ψ, 9 bits for ϕ Reserved if HBF protocol isset to a non-affirmative value, such as 0. HBF Compressed 2 113 If theHBF compression subfield is set to an affirmative Channel Width value,such as 1, this subfield indicates the width of the channel in which themeasurement to create the compressed beamforming feedback matrix wasmade: Set to a non-affirmative value, such as 0, for 2.16 GHz Set to anaffirmative value, such as 1, for 4.32 GHz or 2.16 + 2.16 GHz Set to 2for 6.48 GHz Set to 3 for 8.64 GHz or 4.32 + 4.32 GHz Reserved if HBFprotocol is set to a non-affirmative value, such as 0. HBF Feedback 4115 Option 1: Update the granularity based on 512 subcarriers carriergrouping Ng = 1, 2, 4, 8, 16, 32, 64, 128, 256, 512 Option 2: Bandwidthdependent Grouping HBF Feedback 1 118 Multiplies the carrier grouping bya factor in the case of flat Carrier Grouping channel. Factor 1 4 =>single tap MU-MIMO TBD 119 To indicate the selected STAs and theirassociated antenna Configuration ID configuration: MU-CT signaling, Inthis case bits 17 to 95 are reserved. MU-MIMO No 1 May indicate that noAnnouncement ACK may be sent by ACK the MU-MIMO responders. Set to anon-affirmative value, such as 0, if Grant ACK is required, Set to anaffirmative value, such as 1, if Grant ACK is not required (may beoptional for SU). Reserved xx xx Set to a non-affirmative value, such as0, by the transmitter and ignored by the receiver. CTCS 16  127 Containsthe CRC-16 computed over the content of the control trailer. This fieldis computed.

An EDMG HBF Control Field may be used to manage the exchange of HBFchannel state or transmit beamforming feedback information and to startthe HBF protocol, as shown in the example field of FIG. 30. Row 3010 mayindicate the number of bits allocated to each subfield in row 3020. Thesubfields in row 3020 may use the definitions provided in the exampleshown in Table 6.

TABLE 6 Example HBF Control Field HBF protocol 1 Set to anon-affirmative value, such as 0, to indicate that this controlannouncement trailer is not a HBF announcement. Set to an affirmativevalue, such as 3021 1, to indicate that this control trailer is a HBFprotocol announcement. HBF protocol 1 The value of this field mayindicate the type of HBF protocol requested. type 3022 Set to anon-affirmative value, such as 0, to indicate a Forward HBF Protocol.Set to an affirmative value, such as 1, to indicate a Reverse HBFannouncement. Reserved if HBF protocol is set to a non- affirmativevalue, such as 0. HBF protocol 2 The value of this field may indicatethe type of sounding to be used for Sounding Type the HBF protocol. 0:BRP sounding, 1. Beam tracking sounding 2. 3023 CEF based sounding. 3.Reserved. The Beam Tracking and CEF based sounding may use suitableframes such as the QOS Null. Reserved if HBF protocol is set to anon-affirmative value, such as 0. HBF Information 1 The value of thisfield may indicate whether the HBF Information is in Domain 3024 thefrequency domain (more suitable for OFDM PPDUs) or in the time domain(more suitable for SC PPDUs but can be post-processed for OFDM PPDUs)Set to a non-affirmative value, such as 0, to indicate Time Domainsounding, and set to an affirmative value, such as 1, for FrequencyDomain sounding. Reserved if HBF protocol is set to a non-affirmativevalue, such as 0. HBF Information 1 The value of this field may indicatethe type of HBF information. Set to Feedback Type a non-affirmativevalue, such as 0, to indicated Channel Feedback, and 3025 set to anaffirmative value, such as 1, to indicate Precoder Feedback. Reserved ifHBF protocol is set to a non-affirmative value, such as 0. HBF Feedback1 The value of this field may indicate if the HBF information isCompression 3026 compressed or uncompressed. Set to a non-affirmativevalue, such as 0, to indicate non-compressed HBF information, and set toan affirmative value, such as 1, to indicate Compressed HBF information.Reserved if HBF protocol is set to a non-affirmative value, such as 0.HBF Feedback 1 If the feedback type field is set to a non-affirmativevalue, such as 0, Tap Delay and the HBF protocol field is set to anaffirmative value, such as 1, and Present 3027 the HBF protocol type isset to a non-affirmative value, such as 0, this subfield is set to anaffirmative value, such as 1, to indicate that the Tap Delay subfield ispresent as part of the HBF information. This subfield is sSet to anon-affirmative value, such as 0, in all other cases otherwise. Reservedif HBF protocol is set to a non-affirmative value, such as 0. HBFFeedback 2 If the Tap Delay Present subfield is set to an affirmativevalue, such as Number of Taps 1, this subfield indicates the Number oftaps in each channel Present 3028 measurement: 0x0 - 1 tap 0x1 - 5 4 ×NCB + 1 taps 0x2 - 15 14 × NCB + 1 taps 0x3 - 63 62 × NCB + 1 taps WhereNCB is the integer number of contiguous 2.16 GHz channels over which themeasurement was taken. Reserved if HBF protocol is set to anon-affirmative value, such as 0. HBF Compressed 3 If the HBFcompression subfield is set to an affirmative value, such as Nc Index3029 1, this subfield may indicate the number of columns, Nc, in thecompressed beamforming feedback matrix minus 1: Set to a non-affirmativevalue, such as 0, for Nc = 1 Set to an affirmative value, such as 1, forNc = 2 Set to 7 for Nc = 8 Reserved if HBF protocol is set to anon-affirmative value, such as 0. HBF Compressed 3 If the HBFcompression subfield is set to an affirmative value, such as Nr Index3030 1, this subfield may indicate the number of rows, Nr, in thecompressed beamforming feedback matrix minus 1: Set to a non-affirmativevalue, such as 0, for Nr = 1 Set to an affirmative value, such as 1, forNr = 2 Set to 7 for Nr = 8 Reserved if HBF protocol is set to anon-affirmative value, such as 0. HBF Compressed 1 If the HBFcompression subfield is set to an affirmative value, such as FeedbackType 1, this subfield may indicate if the feedback is for SU-MIMO or MU-3031 MIMO transmission. Set to a non-affirmative value, such as 0, toindicate SU-MIMO and set to an affirmative value, such as 1, to indicateMU-MIMO. Reserved if HBF protocol is set to a non-affirmative value,such as 0. HBF Compressed 1 If the HBF compression subfield is set to anaffirmative value, such as CB Info 3032 1, this subfield may indicatethe size of codebook entries: If Compressed Feedback Type field is SU:Set to a non-affirmative value, such as 0, for 2 bits for ψ, 4 bits for□ Set to an affirmative value, such as 1, for 4 bits for ψ, 6 bits for □If Compressed Feedback Type field is MU: Set to a non-affirmative value,such as 0, for 5 bits for ψ, 7 bits for □ Set to an affirmative value,such as 1, for 7 bits for ψ, 9 bits for □ Reserved if HBF protocol isset to a non-affirmative value, such as 0. HBF Compressed 2 If the HBFcompression subfield is set to an affirmative value, such as ChannelWidth 1, this subfield may indicate the width of the channel in whichthe 3033 measurement to create the compressed beamforming feedbackmatrix was made: Set to a non-affirmative value, such as 0, for 2.16 GHzSet to an affirmative value, such as 1, for 4.32 GHz or 2.16 + 2.16 GHzSet to 2 for 6.48 GHz Set to 3 for 8.64 GHz or 4.32 + 4.32 GHz Reservedif HBF protocol is set to a non-affirmative value, such as 0. HBFFeedback 4 Option 1: Update the granularity based on 512 subcarrierscarrier grouping Ng = 1, 2, 4, 8, 16, 32, 64, 128, 256, 512 3034 Option2: Bandwidth dependent Grouping MU-MIMO TBD To indicate the selectedSTAs and their associated antenna Configuration ID configuration: MU-CTsignaling, In this case bits 17 to 95 are reserved. 3035 MU-MIMO No 1Indicates that no Announcement ACK shall be sent by the MU-MIMO ACK 3036responders. Set to a non-affirmative value, such as 0, if Grant ACK isrequired, Set to an affirmative value, such as 1, if Grant Ack is notrequired (may be optional for SU).

Table 7 shows an example of compressed beamforming frame information.

TABLE 7 Example compressed beamforming frame Order Information 1Category 2 EDMG Action 3 EDMG HBF Control 4 Compressed BeamformingReport

FIG. 31 shows an example of an EDMG HBF Announcement Frame 3100, wherethe STA info may be in the EDMG HBF Control Field or a subset of thefields in the Control Field. As shown, the EDMG HBF Announcement Frame3100 may include a Frame Control field 3101, a Duration field 3102, a RAfield 3103, a TA field 3104, a Sounding Dialog Token 3105, and an STAinformation field 3106.

FIG. 32 shows an example of an EDMG HBF Announcement ACK frame 3200,where both the STA ACK information 3206 and the STA information request3207 fields may be the EDMG HBF Control field or a subset of the fieldsin the Control Field. As shown, the EDMG HBF Announcement ACK Frame 3200may include a Frame Control field 3201, a Duration field 3202, an RAfield 3203, a TA field 3204, a Sounding Dialog Token 3205, an STA ACKinformation field 3206, and an STA information request field 3207.

FIGS. 33A and 33B show an example of an MU-Grant Frame 3300. As show,the MU-Grant Frame 3300 may include a Frame Control field 3301, aDuration field 3302, an RA field 3303, a TA field 3304, a DynamicAllocation Info field 3305, a beamforming sounding field 3307, anislnitiatorTXSS field 3307, an isREspnderTXSS field 3309, an RXSS Lengthfield 3310, a RXSSTxRate field 3311, a MU-MIMO Config_Idi field 3312,and a Reserved field 3313. In the MU-grant frame 3300, a MU-MIMOconfiguration ID 3312 may be added, where there is a number to indicatethe selected STAs and their associated antenna configurations. Theconfigurations may have been communicated to STAs previously through aMIMO selection frame with the MIMO selection frame communicating N,which is a number of MU-MIMO Transmission Configurations. An example ofthese configurations may be MU-MIMO Config_ID 1: (BF1, TXAnt_Sec_ID1/SS_ID1, STA_ID1, RX Ant_Sec_ID1); (BF2, TXAnt_Sec_ID2/SS_ID2, STA_ID2, RX Ant_Sec_ID2), and so on. Continuing theexample, a second example configuration may be MU-MIMO Config_ID 2:(BF1, TX Ant_Sec_ID1/SS_ID1, STA_ID1, RX Ant_Sec_ID1); (BF2, TXAnt_Sec_ID2/SS_ID2, STA_ID2, RX Ant_Sec_ID2), and so on. Furthercontinuing the example, the Nth example configuration may be MU-MIMOConfig._N: (BF1, TX Ant_Sec_ID1/SS_ID1, STA_ID1, RX Ant_Sec_ID1); (BF2,TX Ant_Sec_ID2/SS_ID2, STA_ID2, RX Ant_Sec_ID2), and so on. The BFi bit,where i is a number, may indicate TX Any_Sec_Idi (non-beamed) or SS_IDi(beamformed). The RA may be set to MU-MIMO Group ID and the TA may beset to the MU-MIMO BSSID.

The EDMG Compressed Beamforming Report field may be used by the EDMGCompressed Beamforming feedback to carry explicit feedback informationin the form of angles representing compressed beamforming feedbackmatrices V for use by a transmit beamformer to determine steeringmatrices Q.

The size of the EDMG Compressed Beamforming Report field may depend onthe values in the EDMG MIMO Control field or the EDMG Control Trailer ofparameter CT_TYPE set to GRANT_RTS_CTS2Self. The EDMG CompressedBeamforming Report field contains EDMG Compressed Beamforming Reportinformation. EDMG Compressed Beamforming Report information may alwaysbe included in the VHT Compressed Beamforming feedback.

The EDMG Compressed Beamforming Report information may contain thechannel matrix elements indexed, first, by matrix angles in the ordershown in Table 7 and, second, by data subcarrier index from lowestfrequency to highest frequency.

According to an implementation, feedback may be needed for HBF. Feedbackmay be needed for explicit HBF protocols only and may be send back HBFinformation needed by a transmitter for HBF transmission. The hybridbeamforming information may differ for SC versus OFDM PPDUs.

For SC PPDUs, there may be only time domain information with respect tothe precoder and/or channel. FIG. 34 shows an example of EDMG channelfeedback for SC PPDU mode. For channel HBF information in the SC-PDUmode, it may re-use existing MIMO channel feedback in, for example,802.11ay, as shown in FIG. 34. As shown, the Channel MeasurementFeedback element format 3410 may include an element ID 3431, length3432, an SNR field 3411 with corresponding SNR information 3412, aChannel Measurement field 3413 with corresponding channel measurementinformation 3414, a Tap Delay field 3415 with corresponding tap delayinformation 3416, and a Sector ID order field 3417 with correspondingSector and antenna ID information 3418. As also shown in FIG. 34, a EDMGChannel Measurement Feedback element format 3420 may include an elementID 3433, a Length 3434, an element ID extension 3435, a EDMG Sector IDorder field 3421 with corresponding EDMG Sector ID, TX, and RX AntennaID information 3422, BRP CDOWN field 3423 with corresponding BRP CDOWNinformation 3424, and a Tap Delay field 3425 with corresponding relativedelay tap information 3426.

FIG. 35 shows an example of EDMG precoder feedback for SC PPDU mode. Forprecoder HBF information in the SC PPDU mode, it may re-use the existingMIMO channel feedback framework with elements in the channelmeasurements field set to precoder elements, as shown in FIG. 36. Asshown, the Channel Measurement Feedback element format 3510 may includean element ID 3531, length 3532, an SNR field 3511 with correspondingSNR information 3512, a Beamforming Feedback Matrix field 3513 withcorresponding channel measurement information 3514, a Tap Delay field3515 with corresponding tap delay information 3516, and a Sector IDorder field 3517 with corresponding Sector and antenna ID information3518. As also shown in FIG. 35, an EDMG Channel Measurement Feedbackelement format 3520 may include an element ID 3533, a Length 3534, anelement ID extension 3535, a EDMG Sector ID order field 3521 withcorresponding EDMG Sector ID, TX, and RX Antenna ID information 3522,BRP CDOWN field 3523 with corresponding BRP CDOWN information 3524, anda Tap Delay field 3525 with corresponding relative delay tap information3526.

For OFDM PPDUs, frequency domain precoder information may be available.FIG. 36 shows an example of EDMG HBF feedback for OFDM PPDU mode. Asshown, the Channel Measurement Feedback element format 3610 may includean element ID 3631, length 3632, an SNR field 3611 with correspondingSNR information 3612, a Beamforming Feedback Matrix field 3613 withcorresponding channel measurement information 3614, a Tap Delay field3615 with corresponding tap delay information 3616, and a Sector IDorder field 3617 with corresponding Sector and antenna ID information3618. As also shown in FIG. 36, an EDMG Channel Measurement Feedbackelement format 3620 may include an element ID 3633, a Length 3634, anelement ID extension 3635, a EDMG Sector ID order field 3621 withcorresponding EDMG Sector ID, TX, and RX Antenna ID information 3622,BRP CDOWN field 3623 with corresponding BRP CDOWN information 3624, ascidx field 3625 with corresponding scidx information 3626, and a changein SNR (ΔSNR) field 3627 with corresponding ΔSNR information 3628.Precoder feedback in the OFDM PPDU mode may re-use an existing MIMOchannel feedback framework with elements in the channel measurementfield set to compressed feedback. For an MU-transmission, additionalfields may be added to send feedback for the MU exclusive beamformingreport field and/or the ΔSNR, as shown in FIG. 36.

FIG. 37 shows an example of HBF feedback in a frame for SC and OFDM PPDUmodes. The HBF information for SC and OFDM may use a new frame thatincludes fields for the time domain channel and precoder based SCfeedback and also frequency domain, compressed, precoder-based OFDMfeedback. As shown in FIG. 37, the Channel Measurement Feedback elementformat 3710 may include an element ID 3720, length 3721, an SNR field3711 with corresponding SNR information 3712, aPrecoder/Channel/Beamforming Feedback Matrix field 3713 withcorresponding channel measurement information 3714, a Tap Delay/scidxfield 3715 with corresponding scodx information 3716, and a SNR field3717 with corresponding Sector and antenna ID information 3718.

According to an implementation, one or more frames may be used for theHBF protocol and may include one or more of a Control Trailer (CT) forannouncement, BRP, and/or feedback, an EDMG BRP Request Element for BRPparameters, a DMG Beam Refinement Element for BRP parameters, a MIMOFeedback Control Element for SC and OFDM feedback, and/or HBF FeedbackControl Element for SC and OFDM feedback. Details of the parameterssignaled and example packets they may signal are shown in Table 8.

TABLE 8 Setup/Announcement HBF protocol 1 CT Set to a non-affirmativevalue, such as 0, to indicate that announcement this control trailer isnot a HBF announcement. Set to an affirmative value, such as 1, toindicate that this control trailer is a HBF protocol announcement. HBFprotocol 1 CT The value of this field indicates the type of HBF protocoltype requested. Set to a non-affirmative value, such as 0, to indicatean explicit HBF Protocol. Set to an affirmative value, such as 1, toindicate an implicit HBF announcement. Reserved if HBF protocol is setto a non-affirmative value, such as 0. HBF protocol 1 CT The value ofthis field indicates the type of sounding to Sounding Type be used forthe HBF protocol. 0: BRP sounding, 1. Beam tracking sounding . Reservedif HBF protocol is set to a non-affirmative value, such as 0. SoundingDigital 1 EDMG BRP BRP request for performing digital beamforming.Beamforming Request Element Request HBF Information 1 DMG Beam The valueof this field indicates the type of HBF Feedback Type Refinementinformation. Set to a non-affirmative value, such as 0, to (Request)element: request indicated Channel Feedback, and set to an affirmativevalue, such as 1, to indicate Precoder Feedback. Reserved if HBFprotocol is set to a non-affirmative value, such as 0. Note: if OFDMPPDU, then always set to an affirmative value, such as 1. HBFInformation 1 MIMO Feedback The value of this field indicates the typeof HBF Feedback Type Control element: information. Set to anon-affirmative value, such as 0, to (Response) feedback indicatedChannel Feedback, and set to an affirmative value, such as 1, toindicate Precoder Feedback. Reserved if HBF protocol is set to anon-affirmative value, such as 0. Note: if OFDM PPDU, then always set toan affirmative value, such as 1. HBF Information 1 May default based Thevalue of this field indicates whether the HBF Domain on PPDU Mode. IfInformation is in the frequency domain (more suitable SC, then timedomain, for OFDM PPDUs) or in the time domain (more suitable if OFDMthen for SC PPDUs but can be post-processed for OFDM frequency domain.PPDUs) HBF Feedback 1 May default based The value of this fieldindicates if the HBF information is Compression on PPDU Mode. Ifcompressed or uncompressed. Set to a non-affirmative SC thenuncompressed, value, such as 0, to indicate non-compressed HBF if OFDMthen information, and set to an affirmative value, such as 1,compressed. to indicate Compressed HBF information. Reserved if HBFprotocol is set to a non-affirmative value, such as 0. Feedback (SC) HBFFeedback: 2 CT: If the Tap Delay Present subfield is set to anaffirmative Number of Taps Option 1: as parameter value, such as 1, thissubfield indicates the Number of Requested in CT sent to each STA tapsin each channel measurement: {can be per STA independently, we may 0x0 -1 tap or for all STAs} have a single CT for 0x1 - 4 × NCB + 1 taps eachtransmission 0x2 - 14 × NCB + 1 taps that may change 0x3 - 62 × NCB + 1taps depending on STA. Where NCB is the integer number of contiguous2.16 Option 2: as multiple GHz channels over which the measurement wastaken. parameters in a single CT DMG Beam Refinement element: FBCK-REQfield. For all STAs. Or for specific STA sent multiple times. MIMO SetupControl element format: MIMO- FBCK-REQ (can use existing frame for allSTAs or add extra parameter for per STA). Option 1: use the parametersfrom the MIMO BF setup frame sent during MIMO phase Add MIMO-FBCK-REQfield to CT or new frame. HBF Feedback: 1 MIMO Feedback If the Tap DelayPresent subfield is set to an affirmative Tap Delay Control elementvalue, such as 1, the Tap Delay subfield is present as Present (MIMOFBCK-TYPE part of the MIMO BF feedback. Otherwise, set to a non- field)affirmative value, such as 0. HBF Feedback: 2 MIMO Feedback If the TapDelay Present subfield is set to an affirmative Number of Taps Controlelement value, such as 1, this subfield indicates the Number of Present(MIMO FBCK-TYPE taps in each channel measurement: field) 0x0 - 1 tap0x1 - 4 × NCB + 1 taps 0x2 - 14 × NCB + 1 taps 0x3 - 62 × NCB + 1 tapsWhere NCB is the integer number of contiguous 2.16 GHz channels overwhich the measurement was taken. Reserved if HBF protocol is set to anon-affirmative value, such as 0. Feedback (OFDM) HBF 3 CT: If the HBFcompression subfield is set to an affirmative Compressed Nc Option 1: asparameter value, such as 1, this subfield indicates the number of Indexrequest in CT sent to each STA columns, Nc, in the compressedbeamforming feedback {per be per STA independently, we may matrix minus1: or for all STAs} have a single CT for Set to a non-affirmative value,such as 0, for Nc = 1 each transmission Set to an affirmative value,such as 1, for Nc = 2 that may change . . . depending on STA. Set to 7for Nc = 8 Option 2: as multiple Reserved if HBF protocol is set to anon-affirmative parameters in a single CT value, such as 0. DMG BeamRefinement element: FBCK-REQ field. Note that update may not bepossible. For all STAs. Or for specific STA sent multiple times. MIMOSetup Control element format: MIMO- FBCK-REQ {add Nc to MIMO FBCK-REQ}Option 1: use the parameters from the MIMO BF setup frame sent duringMIMO phase EDMG BRP Request Element (Per STA): not enough space (4 bits)HBF SU/MU 1 Same as above Indicates the Feedback quantization typeFeedback 0 indicates SU Quantization 1 indicates MU request {per be perSTA or for all STAs} HBF 3 MIMO Feedback If the HBF compression subfieldis set to an affirmative Compressed Nc Control Element, value, such as1, this subfield indicates the number of Index response HBF Feedbackcolumns, Nc, in the compressed beamforming feedback Control Element:matrix minus 1: control field; Set to a non-affirmative value, such as0, for Nc = 1 Set to an affirmative value, such as 1, for Nc = 2 . . .Set to 7 for Nc = 8 Reserved if HBF protocol is set to a non-affirmativevalue, such as 0. HBF 3 MIMO Feedback If the HBF compression subfield isset to an affirmative Compressed Nr Control Element, value, such as 1,this subfield indicates the number of Index HBF Feedback rows, Nr, inthe compressed beamforming feedback Control Element: matrix minus 1:control field Set to a non-affirmative value, such as 0, for Nr = 1 Setto an affirmative value, such as 1, for Nr = 2 . . . Set to 7 for Nr = 8Reserved if HBF protocol is set to a non-affirmative value, such as 0.HBF 1 MIMO Feedback If the HBF compression subfield is set to anaffirmative Compressed Control Element, value, such as 1, this subfieldindicates if the feedback Feedback Type HBF Feedback is for SU-MIMO orMU-MIMO transmission. Set to a Control Element: non-affirmative value,such as 0, to indicate SU-MIMO control field and set to an affirmativevalue, such as 1, to indicate MU-MIMO. Reserved if HBF protocol is setto a non-affirmative value, such as 0. HBF 1, MIMO Feedback If the HBFcompression subfield is set to an affirmative Compressed CB TBD ControlElement, value, such as 1, this subfield indicates the size ofInformation HBF Feedback codebook entries: Control Element: IfCompressed Feedback Type field is SU Feedback control field Quantizationresponse: Set to a non-affirmative value, such as 0, for 2 bits for ψ, 4bits for ϕ Set to an affirmative value, such as 1, for 4 bits for ψ, 6bits for ϕ If Compressed Feedback Type field is MU Feedback Quantizationresponse: Set to a non-affirmative value, such as 0, for 5 bits for ψ, 7bits for ϕ Set to an affirmative value, such as 1, for 7 bits for ψ, 9bits for ϕ Reserved if HBF protocol is set to a non-affirmative value,such as 0. SU/MU 1 MIMO Feedback Indicates the Feedback quantizationtype Feedback Control Element, 0 indicates SU Quantization HBF Feedback1 indicates MU response Control Element: control field HBF 2 MIMOFeedback If the HBF compression subfield is set to an affirmativeCompressed Control Element, value, such as 1, this subfield indicatesthe width of the Channel Width HBF Feedback channel in which themeasurement to create the Control Element: compressed beamformingfeedback matrix was made: control field Set to a non-affirmative value,such as 0, for 2.16 GHz Set to an affirmative value, such as 1, for 4.32GHz or 2.16 + 2.16 GHz Set to 2 for 6.48 GHz Set to 3 for 8.64 GHz or4.32 + 4.32 GHz Reserved if HBF protocol is set to a non-affirmativevalue, such as 0. HBF Feedback 4 MIMO Feedback Option 1: Update thegranularity based on 512 carrier grouping Control Element, subcarriersvs 64 subcarriers (and channel model). HBF Feedback Ng = 1, 2, 4, 8, 16,32, 64, 128, 256, 512 Control Element: Option 2: Bandwidth dependentGrouping control field MU-MIMO No 1 CT, Indicates that no AnnouncementACK shall be sent by ACK MIMO Feedback the MU-MIMO responders. Set to anon-affirmative Control Element, value, such as 0, if Grant ACK isrequired, Set to an HBF Feedback affirmative value, such as 1, if GrantAck is not required Control Element: (may be optional for SU). controlfield

Although embodiments and examples described herein discuss placinginformation, types information, or fields in specific frames/fields,however, it is understood that the information, types of information, orfields may be placed within any frame/field to enable any of the desiredfunctionality/features as discussed herein. The disclosed fields may becombined with existing or new packets. In other words, the placement ofthe fields disclosed herein is not limited to the examples andembodiments discussed, but may be implemented in any packet or field.

Although embodiments and examples described herein consider 802.11specific protocols, it is understood that the features described hereinare not restricted to these scenarios and are applicable to otherwireless systems as well. Although features and elements are describedabove in particular combinations, one of ordinary skill in the art willappreciate that each feature or element can be used alone or in anycombination with the other features and elements. In addition, themethods described herein may be implemented in a computer program,software, or firmware incorporated in a computer-readable medium forexecution by a computer or processor. Examples of computer-readablemedia include electronic signals (transmitted over wired or wirelessconnections) and computer-readable storage media. Examples ofcomputer-readable storage media include, but are not limited to, a readonly memory (ROM), a random access memory (RAM), a register, cachememory, semiconductor memory devices, magnetic media such as internalhard disks and removable disks, magneto-optical media, and optical mediasuch as CD-ROM disks, and digital versatile disks (DVDs). A processor inassociation with software may be used to implement a radio frequencytransceiver for use in a WTRU, UE, terminal, base station, RNC, or anyhost computer.

What is claimed is:
 1. A station (STA), the STA comprising: a processor;and a transceiver; the processor and the transceiver configured tosense, using at least one of a plurality of antenna chains, radiofrequency (RF) energy on a channel in a first time duration, wherein thelevel of RF energy sensed during the first time duration indicates thatthe channel is busy; the processor and the transceiver configured tosense, using the at least one of the plurality of antenna chains, RFenergy on the channel in a second time duration, wherein the level of RFenergy sensed during the second time duration indicates that the channelis not busy; the processor and the transceiver configured to, based onthe energy level sensed during the second time duration, send a frameusing the at least one of the plurality of antenna chains, wherein theframe indicates timing information associated with a multipleinput-multiple output (MIMO) transmission to be sent by the STA; and thetransceiver configured to send the MIMO transmission on the channelusing the indicated timing information and the at least one of theplurality of antenna chains.
 2. The STA of claim 1, wherein the frame isa request-to-send (RTS) frame.
 3. The STA of claim 2, the processor andthe transceiver configured to receive, in response to the RTS frame, atleast one clear-to-send (CTS) frame, wherein the MIMO transmission issent at least an interframe space after the at least one received CTSframe.
 4. The STA of claim 3, wherein the MIMO transmission is asingle-user (SU) MIMO transmission, and wherein the at least one CTSframe is received using beamforming parameters associated withbeamforming parameters used to transmit the RTS frame.
 5. The STA ofclaim 3, wherein the MIMO transmission is a multi-user (MU) MIMOtransmission and wherein the CTS frame is a CTS-to-self frame.
 6. TheSTA of claim 1, the processor and the transceiver configured to detectsignals on the channel in the first time duration and in the second timeduration, wherein a signal strength of at least one signal detected inthe first time duration indicates that the channel is busy, and whereina signal strength of at least one signal detected in the second timeduration indicates that the channel is not busy.
 7. The STA of claim 1,wherein the MIMO transmission includes at least one field for use in abeamforming training procedure.
 8. The STA of claim 7, configured as aninitiating STA of the beamforming training procedure.
 9. The STA ofclaim 8, the processor and the transceiver configured to receive, inresponse to the MIMO transmission, channel feedback associated with theat least one field from a responding STA of the beamforming trainingprocedure.
 10. The STA of claim 7, wherein the at least one field is atraining (TRN) field.
 11. A method performed by a station (STA), themethod comprising: sensing, using at least one of a plurality of antennachains, radio frequency (RF) energy on a channel in a first timeduration, wherein the level of RF energy sensed during the first timeduration indicates that the channel is busy; sensing, using the at leastone of the plurality of antenna chains, RF energy on the channel in asecond time duration, wherein the level of RF energy sensed during thesecond time duration indicates that the channel is not busy; sending,based on the energy sensed during the second time duration, a frameusing the at least one of the plurality of antenna chains, wherein theframe indicates timing information associated with a multipleinput-multiple output (MIMO) transmission to be sent by the STA; andsending the MIMO transmission on the channel using the indicated timinginformation and the at least one of the plurality of antenna chains. 12.The method of claim 11, wherein the frame is a request-to-send (RTS)frame.
 13. The method of claim 12 comprising receiving, in response tothe RTS frame, at least one clear-to-send (CTS) frame, wherein the MIMOtransmission is sent at least an interframe space after the at least onereceived CTS frame.
 14. The method of claim 13, wherein the MIMOtransmission is a single-user (SU) MIMO transmission, and wherein the atleast one CTS frame is received using beamforming parameters associatedwith beamforming parameters used to transmit the RTS frame.
 15. Themethod of claim 13, wherein the MIMO transmission is a multi-user (MU)MIMO transmission and wherein the CTS frame is a CTS-to-self frame. 16.The method of claim 11 comprising detecting signals on the channel inthe first time duration and in the second time duration, wherein asignal strength of at least one signal detected in the first timeduration indicates that the channel is busy, and wherein a signalstrength of at least one signal detected in the second time durationindicates that the channel is not busy.
 17. The method of claim 11,wherein the MIMO transmission includes at least one field for use in abeamforming training procedure.
 18. The method of claim 7, wherein theSTA is configured as an initiating STA of the beamforming trainingprocedure.
 19. The method of claim 18 comprising receiving, in responseto the MIMO transmission, channel feedback associated with the at leastone field from a responding STA of the beamforming training procedure.20. The method of claim 17, wherein the at least one field is a training(TRN) field.